Where can one find a new handle for rear door? it is typical on several models.

how did it break?

i've never seen one bust, but i pulled one of my rear handles off the door once,
i was really surprised to find that the handle that pulls down a heavy 3000 pound rated door was only screwed into plywood with two 1/2" screws.
they ought to at least run a bolt thru it and the door with a large washer on the back. i would have ponied up with the extra buck.

I'd ask this question of the manufacture of the trailer, don't really know where you would get one aftermarket.