PetaPocoAzure with composite primary keys is forked from Brad Robinson of Topten Software's PetaPoco v5, with added support for SQL Azure (ReliableSqlConnection) and composite primary keys.
PetaPoco v5 (from which this is forked) is currently not deployed to NuGet because it 'shouldn't be considered production quality' according to Brad. This is a quick-and-dirty change (no tests) to support SQL Azure and composite primary keys - so expect it to be even less 'production quality'!
See here - http://www.toptensoftware.com/petapoco - for full details of the original project.