I'm guessing that it's do-able. I still have my old door with that section of cladding removed. Lemme know if it would help to post a pic of what's behind the cladding.

If I were trying to straighten it, I think I'd make a sacrificial tool (unless you have access to some body shop tools). Take a 2x6 about 3 feet long. Cut a 1 inch wide, 4 inch deep knotch in one end (sorta like a 2 prong fork). Use it to try and bend the damage out ... GENTLY.