I was trying to use svcutil.exe to generate proxy classes for a service but when I use the /reference
option to reference an assembly that is built for .NET 4.0 I g
I'm having the same problem.
Microsoft says that you can only use .Net 4 DLLs with the new SvcUtil that comes wit the latest version of .Net (http://msdn.microsoft.com/en-us/library/aa347733.aspx) but that version seems to be the one you are mentioning above. It won't access .Net 4 DLLs as references at all.