Help! Reframing broken door. Can't find the right part..

Hi folks. I'm in the process of rehabbing a 1995 Sunline Solaris and am having a heck of a time finding what I need to finish the door! One of the doors was ripped off of the body during transit before I purchased it. As a result it the door itself is missing 3/4ths of the aluminum frame. I can't find anything comparable on the internet to replace it with.

For reference, I'm talking about the aluminum U-shaped frame on the door itself that has a slot to hold the weather stripping. Can anyone help me?

Thanks in advance!