Rusty ext. hatch gaskets!

[Del Gurney]

Soooo, I finally got around to waxing "Tinbad" and in doing so I saw rust particles falling out of the rear "trunk" gasket. Seems the steel material used as "clamping" the gasket to the compartment frame is shot.
Is there a better means/material to seal the exterior compartments????

2nd question:::: the rear "trunk" door is very hard to close and won't close at all unless the trailer is only sitting on it's tires with out the levelers even slightly "over tensioned". Right now the whole trailer is sitting on a combo. of cinder blocks (under the trailer tongue and factory marked "jack" decal aft of the axel) and 4 jack stands (under the longitudinal frame forward of the axel) with the tires only "kissing" the concrete floor. I made sure that all supports carried an equal load.......
Should I have a custom hatch made slightly smaller??