Shared classes are build under VS2008 only but not under MSBuild

We share our classes between silverlight 3.0 client and server as is it described here. Everything works fine under Visual Studio 2008 only. Using msbuild with following command line parameters:

C:\Windows\Microsoft.NET\Framework\v3.5\msbuild.exe FoobarApplication.sln /t:Rebuild /p:Configuration=Release /p:Platform="Any CPU"

we get follo开发者_JS百科wing error:

Class1.cs(28,54): error CS0234: The type or namespace name 'WcfService' does not exist in the namespace 'Company.FoobarApplication' (are you missing an assembly reference?)
Service References\geoServiceReference1\Reference.cs(24,81): error CS0234: The type or namespace name 'WcfService' does not exist in the namespace 'Company.FoobarApplication' (are you missing an assembly reference?)
Done Building Project "C:\work\bov-tmp\FoobarApplication\SilverlightClassLibrary3\SilverlightClassLibrary3.csproj" (Rebuild target(s)) -- FAILED.

Done Building Project "C:\work\bov-tmp\FoobarApplication\FoobarApplication.sln" (Rebuild target(s)) -- FAILED.

I found exactly the same question here. There are 4 workarounds there, I tried first 3 of them and those did not worked out. The 4-th workaround is not the acceptable solution.

Any thoughts how to build the solution?

Resolved the problem. The geoServiceReference1 project was referencing our RUI.Web project. That stupid reference appeared somehow after the solution reorganization.