If you unlock the MapSource maps using the program [Only registered and activated users can see links. ] you should get a message that they are "Not Lockable" when done. You'll be able to create an IMG file and copy it to the GPS. However you need to unlock the IMG file using the program [Only registered and activated users can see links. ] or else when you turn on the GPS you get a message that there are no maps that support routing, because Garmin locked the maps.

It's far easier going this route than to play with hacked EXEs.