When faced with the same problem. I did not want to take the bolts lose from the trailer. I was afraid I would have to remove the inner skin if I had the same problem as stated above.
My approach was to remove the door from the hinges. Not a difficult task as it turned out. I removed the inner skin of the door to find that there were 4 bolts holding the door on the hinges. Actually they are studs, just unscrewed the four nuts and the door could be removed.
I've attached a photo of one of the hinge fastener assembly.
In looking at photos of an Excella it looks like you have the same hinge setup.
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