The Legend, the reason that you may not be able to see the files in the Add References dialog, is because although the files are installed correctly into the Global Assembly Cache, the files must also exist in a sub folder of where your Visual Studio installation exists. This folder, by default, is located at the following path:
"C:/Program Files/Microsoft Visual Studio 9.0/Common/IDE/PublicAssemblies"
Now if your Visual Studio installation is located in a different folder on your system, you will need to move the files as described above, into the same relative folder "Common/IDE/PublicAssemblies" of your Visual Studio installation.
Once moved, you should see the three files under the .NET tab of the References dialog.
Paul.