Visual-studio – How to add more than one project/solution on the same path to TFS

I am working on a C# project which must be built for more than one platform (.Net and CF.Net) and from past experiences I have found that the best approach that works for me is to have multiple parallel solutions present side by side in the same folder corresponding to each platform. All the code files, resources etc are shared by these projects/solutions and are common for all parallel projects.

Eg.

    /SolutionFolder  
        MySolution.sln  
        MySolution_CE.sln  
        /MyProject  
            MyProject.csproj  
            MyProject_CE.csproj  

Now the problem is once I add MySolution.sln to source control I cannot add MySolution_CE.sln. It says something on the lines of "Cannot add two solutions on the same path".

<edit>
To answer ctake's question, I am trying to add the solution from VS2008 by right clicking on the solution and saying "Add to source control".

Also I forgot to mention that I added the solutions manually anyway but VS2008 does not bind to this solution i.e. the files cannot be checked in/out from these "forced" solutions from within VS2008.
</edit>