[Killer Bee]

like mentioned above, I find it easiest to drill the heads off, remove the panel, and deal with the screw shanks that are left..

grooming the heads of the screws with the panel on is asking for trouble, very difficult to work there without damaging panel..

sharp drill bits, strong low speed drill, patience.. use controlled pressure to get big chips but don't want to run off into the vinyl..

once the panel is removed, soak screws with copious amounts of pb blaster, kroil, wd, whatever penetrant you prefer..

use vice grips with a good sharp jaws and square edges that will allow it to bite every bit of what's protruding..

don't want to mangle what's left into a nub, get a solid bite and work it loose..

sometimes the corrosion is heavier on the tail of the threads (part inside the door) so it may thread in or tighten easier than out..

not far, just enough to break it loose and then work it back and forth, a little more loosen each time until it runs all the way out..

chase the threads with a tap and lube.. I believe mine were all 1/4"-20 but you'll need to verify that on your doors..

by the way, I've had to do this for several screws out of each of the four sets of panels I have removed so don't feel bad..

good luck!