Auto body repair & detailing: Truck Mirror Replacement, allen head screws, power mirror

Question
I am needing to replace the passenger side mirror on my 1994 F-150. It is also a power mirror. I got one of the allen head screws out, but the other wants to round out. Any suggestions on how to get it out. I could probably cut the head off, but wanted to try other options first.
Thanks for any tips.

Answer
take a dremmel tool with a cut of wheel, and cut a slot into it. Then, a flat head screwdriver may get it out. You can also try drilling the head off of the bolt, and once the mirror is removed, take a pair of vice grips to remove the stud, if that applies to your situation. Bill