The gmap version has worked very well for me in unlocking the contents of the gmap folder in the Mapsource installer for Europe 2011.20.
I already had an earlier version of Mapsource installed, so did not bother with the msi. I just parked the gmap folder in a temporary folder, extracted the rar file contents into the gmap folder and ran the bat file. It takes a bit of time to run through all 299 gmp files, but the command window shows progress.
Once completed I just deleted the unlock files and copied the gmap folder to the place where all the other gmap folder are installed on my PC (that varies between XP, Vista etc).
Ran the existing version of Mapsource, it detected the new map, and notes it is not lockable. Sent it to an SD card and it works in the Garmin device.
So no patching of Mapsource, MapInstaller and no need for keygen. Neat!