How to prevent MSBUILD from copying dependent GAC assemblies to bin

I have a msbuild task that 开发者_开发百科builds my solution and I am migrating it from .net 3.5 to 4.0. I have some dependent DLLs that have Local Copy set to true. The 4.0 version of msbuild is not only copying the dependent DLL (which I want), it is also copying all dependent assemblies of that DLL from the 32 bit version of the GAC to my bin. Not only do I not want these files being copied from the GAC, I especially do not want the 32 bit versions for this 64 bit build.

Has the behavior changed in msbuild 4.0? And does anyone know how to force msbuild to use the behavior in 3.5?

Have you ensured that the Copy Local setting is false on those items you don't want copied? If so have you tried tried Setting False on the assemblies you don't want copied locally?

    <Reference Include="System.Core">
      <Private>False</Private>
    </Reference>