This is an F.Y.I. from someone who has spent days researching the subject. First thing first, yes it is possible. Second, it has been done. Thanks to CellZealot & the rest of Team Black Hat for making it possible. They are my heros and they rock! Back to the FYI, the problem resides with the firmware of the radio module itself. TBH came up with a .zip file to update it. I will link to the page but I HIGHLY recommend you don't just download the zip file and try to flash it. I would recommend you reading the thread and thanking CellZealot and TBH for their hard work as figuring something like this out and making a zip file for the rest of us was not at all easy.
HTML:
http://www.mydroidworld.com/forums/android-hacks/8942-tbh-us-gsm-band-unlock-droid-2-global-pro-update-zip-public-release.html