 <p>I experienced this same situation a while back and created a small utility I called "InternalsVisibleToInjector". It uses ILDASM and ILASM to disassemble, modify, and reassemble and assembly with the assembly name of my selection added to the InternalsVisibleTo list for the target assembly. It worked quite well in my situation.</p> <p>I have posted the source code (VS 2008 C# WinForm) for the utility here:</p> <p><a href="http://www.schematrix.com/downloads/InternalsVisibleToInjector.zip" rel="nofollow noreferrer">http://www.schematrix.com/downloads/InternalsVisibleToInjector.zip</a></p> <p>This may not work if the assembly is signed. Please take all appropriate precautions (i.e. make a backup of the assembly before using this and ensure you are on solid legal ground, etc.) </p>