Removal of rear door panel on '93 S320

[Kopfschmerzen]

Hello - I'm new to the forum and to MB ownership. Bought a 1993 with 25,000 mi on it, and a couple months into it my driver's side rear window has gotten stuck half way down (or up, depending on how you look at it!). I'm trying to remove the door panel to get a better look, and so far I have unpopped the bottom portion, but something in the middle of the door panel seems to be bolted. I can't find where that bolt or screw would be. Any advice or links would be much appreciated.