Nevermind, doesn't work after all
If you're on a non Verizon network, you're probably familiar with the consant popping up of "Data connectivity lost. Data Roaming is turned off" notification and also the Data roaming option (in Settings -> Battery & data manager -> Data delivery) not sticking.
Well I found a simple fix, for rooted phones.
You need to edit the /system/build.prop file (I did it on my computer, but you can use notepad on the phone as well) and add a line:at the very end.Code:ro.com.android.dataroaming=true
Then just reboot the phone and enable Data roaming.
Don't forget that you need r+w access to the system folder in order to save the file. ES File Explorer can do that for example.
Also saving the file with the phone's notepad directly didn't work for me. Had to save it to SD first and then copy it to /system and overwrite.
Tested on my Droid 2 Global running .608 stock GB.