RIA Services SP1 build errors: csdlPath cannot be null

We're trying to integrate RIA Services SP1 with one of our existing EF models; we're getting this strange build error, on one of the development machines and on the TFS build server, but other dev machines can build without a problem. I've given up on tryi开发者_高级运维ng to find differences between the machines - any idea what the problem could be?

C:\Program Files (x86)\MSBuild\Microsoft\Silverlight\v4.0\Microsoft.Ria.Client.targets (304): Value cannot be null. Parameter name: csdlPath

Our EF model is somewhat customized - we needed to support both SQL Server and Oracle, and we have separate SSDL files for each; however, RIA shouldn't have anything to do with that, right? And even if it did, some of the dev machines can build and run the solution without a problem.

Help?

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Well, Colin Blair pointed out that the RIA build task does parse the CSDL files when you use vanilla entities (not pocos), in order to find any additional information for automatically applied validation attributes etc.

It seems the answer is to generate matching csdl and msl files (the RIA task does a GroupBy on the resource names without extension). Still not sure why it worked on some machines though... maybe GroupBy returns the groups in a different order and only the first match is processed? Not sure yet.