C:\Program Files\Microsoft Visual Studio 10.0\VC>datasvcutil /out:c:\temp\datasvc.cs /uri:http://devserver/DataService.svc/ /dataservicecollection /language:CSharp /version:2.0
It will complain if you specify /dataservicecollection and not a version. I was surprised to see all the code this generated, I think all the GUI stuff neglected to create this file for me. This has all the tedious code for updating if a any single property changes in an entity.