diff --git a/pbm/client.go b/pbm/client.go
index d8d2131cf..131cb65d9 100644
--- a/pbm/client.go
+++ b/pbm/client.go
@@ -49,6 +49,7 @@ type Client struct {
 
 func NewClient(ctx context.Context, c *vim25.Client) (*Client, error) {
 	sc := c.Client.NewServiceClient(Path, Namespace)
+	sc.Cookie = sc.SessionCookie // vcSessionCookie soap.Header
 
 	req := types.PbmRetrieveServiceContent{
 		This: ServiceInstance,
diff --git a/pbm/client_test.go b/pbm/client_test.go
index 0500e0509..1adef3b7e 100644
--- a/pbm/client_test.go
+++ b/pbm/client_test.go
@@ -346,3 +346,28 @@ func TestSupportsEncryption(t *testing.T) {
 		})
 	})
 }
+
+func TestClientCookie(t *testing.T) {
+	simulator.Test(func(ctx context.Context, c *vim25.Client) {
+		pbmc, err := pbm.NewClient(ctx, c)
+		assert.NoError(t, err)
+		assert.NotNil(t, pbmc)
+
+		// Using default / expected Header.Cookie.XMLName = vcSessionCookie
+		ok, err := pbmc.SupportsEncryption(ctx, pbmsim.DefaultEncryptionProfileID)
+		assert.NoError(t, err)
+		assert.True(t, ok)
+
+		// Using invalid Header.Cookie.XMLName = myCookie
+		myCookie := c.SessionCookie()
+		myCookie.XMLName.Local = "myCookie"
+
+		pbmc.Client.Cookie = func() *soap.HeaderElement {
+			return myCookie
+		}
+
+		ok, err = pbmc.SupportsEncryption(ctx, pbmsim.DefaultEncryptionProfileID)
+		assert.EqualError(t, err, "ServerFaultCode: NotAuthenticated")
+		assert.False(t, ok)
+	})
+}
diff --git a/pbm/simulator/simulator.go b/pbm/simulator/simulator.go
index 7478b44fa..03fde5821 100644
--- a/pbm/simulator/simulator.go
+++ b/pbm/simulator/simulator.go
@@ -56,6 +56,7 @@ func New() *simulator.Registry {
 	r := simulator.NewRegistry()
 	r.Namespace = pbm.Namespace
 	r.Path = pbm.Path
+	r.Cookie = simulator.SOAPCookie
 
 	r.Put(&ServiceInstance{
 		ManagedObjectReference: pbm.ServiceInstance,
diff --git a/simulator/registry.go b/simulator/registry.go
index b40b755c3..749efb7b2 100644
--- a/simulator/registry.go
+++ b/simulator/registry.go
@@ -78,6 +78,7 @@ type Registry struct {
 	Namespace string
 	Path      string
 	Handler   func(*Context, *Method) (mo.Reference, types.BaseMethodFault)
+	Cookie    func(*Context) string
 
 	tagManager tagManager
 }
diff --git a/simulator/session_manager.go b/simulator/session_manager.go
index 85ed81538..5a80094b8 100644
--- a/simulator/session_manager.go
+++ b/simulator/session_manager.go
@@ -329,12 +329,29 @@ type Context struct {
 	Map     *Registry
 }
 
+func SOAPCookie(ctx *Context) string {
+	if cookie := ctx.Header.Cookie; cookie != nil {
+		return cookie.Value
+	}
+	return ""
+}
+
+func HTTPCookie(ctx *Context) string {
+	if cookie, err := ctx.req.Cookie(soap.SessionCookieName); err == nil {
+		return cookie.Value
+	}
+	return ""
+}
+
 // mapSession maps an HTTP cookie to a Session.
 func (c *Context) mapSession() {
-	if cookie, err := c.req.Cookie(soap.SessionCookieName); err == nil {
-		if val, ok := c.svc.sm.getSession(cookie.Value); ok {
-			c.SetSession(val, false)
-		}
+	cookie := c.Map.Cookie
+	if cookie == nil {
+		cookie = HTTPCookie
+	}
+
+	if val, ok := c.svc.sm.getSession(cookie(c)); ok {
+		c.SetSession(val, false)
 	}
 }
 
diff --git a/simulator/simulator.go b/simulator/simulator.go
index 71c0037cd..e40f2fc29 100644
--- a/simulator/simulator.go
+++ b/simulator/simulator.go
@@ -1,5 +1,5 @@
 /*
-Copyright (c) 2017-2023 VMware, Inc. All Rights Reserved.
+Copyright (c) 2017-2024 VMware, Inc. All Rights Reserved.
 
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
@@ -497,7 +497,6 @@ func (s *Service) ServeSDK(w http.ResponseWriter, r *http.Request) {
 		Map:     s.sdk[r.URL.Path],
 		Context: context.Background(),
 	}
-	ctx.Map.WithLock(ctx, s.sm, ctx.mapSession)
 
 	var res soap.HasFault
 	var soapBody interface{}
@@ -511,6 +510,7 @@ func (s *Service) ServeSDK(w http.ResponseWriter, r *http.Request) {
 			// Redirect any Fetch method calls to the PropertyCollector singleton
 			method.This = ctx.Map.content().PropertyCollector
 		}
+		ctx.Map.WithLock(ctx, s.sm, ctx.mapSession)
 		res = s.call(ctx, method)
 	}
 
diff --git a/ssoadmin/client.go b/ssoadmin/client.go
index 1b178ddb0..58a557bf1 100644
--- a/ssoadmin/client.go
+++ b/ssoadmin/client.go
@@ -1,11 +1,11 @@
 /*
-Copyright (c) 2018-2023 VMware, Inc. All Rights Reserved.
+Copyright (c) 2018-2024 VMware, Inc. All Rights Reserved.
 
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
 You may obtain a copy of the License at
 
-    http://www.apache.org/licenses/LICENSE-2.0
+http://www.apache.org/licenses/LICENSE-2.0
 
 Unless required by applicable law or agreed to in writing, software
 distributed under the License is distributed on an "AS IS" BASIS,
diff --git a/sts/client.go b/sts/client.go
index c51ec2a00..5c2eaed73 100644
--- a/sts/client.go
+++ b/sts/client.go
@@ -1,11 +1,11 @@
 /*
-Copyright (c) 2018-2023 VMware, Inc. All Rights Reserved.
+Copyright (c) 2018-2024 VMware, Inc. All Rights Reserved.
 
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
 You may obtain a copy of the License at
 
-    http://www.apache.org/licenses/LICENSE-2.0
+http://www.apache.org/licenses/LICENSE-2.0
 
 Unless required by applicable law or agreed to in writing, software
 distributed under the License is distributed on an "AS IS" BASIS,
diff --git a/vim25/soap/client.go b/vim25/soap/client.go
index d3e9e093b..7b4b26ab6 100644
--- a/vim25/soap/client.go
+++ b/vim25/soap/client.go
@@ -1,5 +1,5 @@
 /*
-Copyright (c) 2014-2023 VMware, Inc. All Rights Reserved.
+Copyright (c) 2014-2024 VMware, Inc. All Rights Reserved.
 
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
@@ -86,7 +86,11 @@ type Client struct {
 	Types     types.Func `json:"types"`
 	UserAgent string     `json:"userAgent"`
 
-	cookie          string
+	// Cookie returns a value for the SOAP Header.Cookie.
+	// This SOAP request header is used for authentication by
+	// API endpoints such as pbm, vslm and sms.
+	// When nil, no SOAP Header.Cookie is set.
+	Cookie          func() *HeaderElement
 	insecureCookies bool
 
 	useJSON bool
@@ -210,6 +214,16 @@ func (c *Client) NewServiceClient(path string, namespace string) *Client {
 	return c.newServiceClientWithTransport(path, namespace, c.t)
 }
 
+// SessionCookie returns a SessionCookie with value of the vmware_soap_session http.Cookie.
+func (c *Client) SessionCookie() *HeaderElement {
+	for _, cookie := range c.Jar.Cookies(c.URL()) {
+		if cookie.Name == SessionCookieName {
+			return &HeaderElement{Value: cookie.Value}
+		}
+	}
+	return nil
+}
+
 func (c *Client) newServiceClientWithTransport(path string, namespace string, t *http.Transport) *Client {
 	vc := c.URL()
 	u, err := url.Parse(path)
@@ -234,14 +248,6 @@ func (c *Client) newServiceClientWithTransport(path string, namespace string, t
 	// Copy the cookies
 	client.Client.Jar.SetCookies(u, c.Client.Jar.Cookies(u))
 
-	// Set SOAP Header cookie
-	for _, cookie := range client.Jar.Cookies(u) {
-		if cookie.Name == SessionCookieName {
-			client.cookie = cookie.Value
-			break
-		}
-	}
-
 	// Copy any query params (e.g. GOVMOMI_TUNNEL_PROXY_PORT used in testing)
 	client.u.RawQuery = vc.RawQuery
 
@@ -718,8 +724,10 @@ func (c *Client) soapRoundTrip(ctx context.Context, reqBody, resBody HasFault) e
 		h.ID = id
 	}
 
-	h.Cookie = c.cookie
-	if h.Cookie != "" || h.ID != "" || h.Security != nil {
+	if c.Cookie != nil {
+		h.Cookie = c.Cookie()
+	}
+	if h.Cookie != nil || h.ID != "" || h.Security != nil {
 		reqEnv.Header = &h // XML marshal header only if a field is set
 	}
 
diff --git a/vim25/soap/json_client.go b/vim25/soap/json_client.go
index ca5075de3..b5d25b596 100644
--- a/vim25/soap/json_client.go
+++ b/vim25/soap/json_client.go
@@ -1,5 +1,5 @@
 /*
-Copyright (c) 2023-2023 VMware, Inc. All Rights Reserved.
+Copyright (c) 2023-2024 VMware, Inc. All Rights Reserved.
 
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
@@ -71,8 +71,10 @@ func (c *Client) invoke(ctx context.Context, this types.ManagedObjectReference,
 		return err
 	}
 
-	if len(c.cookie) != 0 {
-		req.Header.Add(sessionHeader, c.cookie)
+	if c.Cookie != nil {
+		if cookie := c.Cookie(); cookie != nil {
+			req.Header.Add(sessionHeader, cookie.Value)
+		}
 	}
 
 	result, err := getSOAPResultPtr(res)
@@ -156,8 +158,10 @@ func isError(statusCode int) bool {
 // session header.
 func (c *Client) checkForSessionHeader(resp *http.Response) {
 	sessionKey := resp.Header.Get(sessionHeader)
-	if len(sessionKey) > 0 {
-		c.cookie = sessionKey
+	if sessionKey != "" {
+		c.Cookie = func() *HeaderElement {
+			return &HeaderElement{Value: sessionKey}
+		}
 	}
 }
 
diff --git a/vim25/soap/json_client_test.go b/vim25/soap/json_client_test.go
index 7511a23ab..7ef6eec26 100644
--- a/vim25/soap/json_client_test.go
+++ b/vim25/soap/json_client_test.go
@@ -1,5 +1,5 @@
 /*
-Copyright (c) 2023-2023 VMware, Inc. All Rights Reserved.
+Copyright (c) 2023-2024 VMware, Inc. All Rights Reserved.
 
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
@@ -206,7 +206,9 @@ func TestFullRequestCycle(t *testing.T) {
 	c := NewClient(addr, true)
 	c.Namespace = "urn:vim25"
 	c.Version = "8.0.0.1"
-	c.cookie = "(original)"
+	c.Cookie = func() *HeaderElement {
+		return &HeaderElement{Value: "(original)"}
+	}
 	c.UseJSON(true)
 
 	c.Transport = &mockHTTP{
diff --git a/vim25/soap/soap.go b/vim25/soap/soap.go
index a8dc121ba..d7703ae8f 100644
--- a/vim25/soap/soap.go
+++ b/vim25/soap/soap.go
@@ -1,11 +1,11 @@
 /*
-Copyright (c) 2014-2018 VMware, Inc. All Rights Reserved.
+Copyright (c) 2014-2024 VMware, Inc. All Rights Reserved.
 
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
 You may obtain a copy of the License at
 
-    http://www.apache.org/licenses/LICENSE-2.0
+http://www.apache.org/licenses/LICENSE-2.0
 
 Unless required by applicable law or agreed to in writing, software
 distributed under the License is distributed on an "AS IS" BASIS,
@@ -21,12 +21,18 @@ import (
 	"github.com/vmware/govmomi/vim25/xml"
 )
 
+// HeaderElement allows changing the default XMLName (e.g. Cookie's default of vcSessionCookie)
+type HeaderElement struct {
+	XMLName xml.Name
+	Value   string `xml:",chardata"`
+}
+
 // Header includes optional soap Header fields.
 type Header struct {
-	Action   string      `xml:"-"`                         // Action is the 'SOAPAction' HTTP header value. Defaults to "Client.Namespace/Client.Version".
-	Cookie   string      `xml:"vcSessionCookie,omitempty"` // Cookie is a vCenter session cookie that can be used with other SDK endpoints (e.g. pbm).
-	ID       string      `xml:"operationID,omitempty"`     // ID is the operationID used by ESX/vCenter logging for correlation.
-	Security interface{} `xml:",omitempty"`                // Security is used for SAML token authentication and request signing.
+	Action   string         `xml:"-"`                         // Action is the 'SOAPAction' HTTP header value. Defaults to "Client.Namespace/Client.Version".
+	Cookie   *HeaderElement `xml:"vcSessionCookie,omitempty"` // Cookie is a vCenter session cookie that can be used with other SDK endpoints (e.g. pbm, vslm).
+	ID       string         `xml:"operationID,omitempty"`     // ID is the operationID used by ESX/vCenter logging for correlation.
+	Security interface{}    `xml:",omitempty"`                // Security is used for SAML token authentication and request signing.
 }
 
 type Envelope struct {
diff --git a/vslm/client.go b/vslm/client.go
index 4bbb70b59..5cfb8a0b7 100644
--- a/vslm/client.go
+++ b/vslm/client.go
@@ -46,6 +46,8 @@ type Client struct {
 
 func NewClient(ctx context.Context, c *vim25.Client) (*Client, error) {
 	sc := c.Client.NewServiceClient(Path, Namespace)
+	sc.Cookie = sc.SessionCookie // vcSessionCookie soap.Header
+
 	req := types.RetrieveContent{
 		This: ServiceInstance,
 	}