Linking Mixed Mode and Managed Assemblies

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I have a managed C++ project and two C# projects. All are class library
projects. The C++ project links with native C++ static libraries and
references to one C# project. The projects structure goes something like this.

Proj2_MCPP --(references)--Proj1_CSharp
Proj3_CSharp --(references)--Proj2_MCPP and Proj1_CSharp

My objective is to link the DLLs produced by the 3 projects into a single DLL.

I tried the following scenario.
1. csc Proj1_CSharp into a netmodule
2. cl Proj2_MCPP with /LN and /clr:oldSyntax switch to produce .obj files
3. csc Proj3_CSharp with /AddModule option and use .netmodule and .obj files
as input
4. Link 1, 2 and 3 into a dll.

and I also tried this.
1. csc Proj1_CSharp into a netmodule
2. Build Proj2_MCPP from VS.NET 2005 (based on
http://support.microsoft.com/kb/309805) to produce .netmodule and obj .files.
3. csc Proj3_CSharp with /AddModule option and use .netmodule and .obj files
as input
4. Link 1, 2 and 3 into a dll.

I never managed to reach step 4. I just stuck with error messages resulted
from step 3.

Am I doing the right thing? Or it is just not possible?

Thanks - Henry