For the benifit of people like me, I wanted to outline the steps to remove the rear panel of the 95 C280. It took me two days to figure it out, and ten minutes to do the job once I stumbled onto the technique.
1. Remove plastic insert from interior door handle.
2. Remove single phillips head screw that is exposed.
3. Revove phillips head screw from near the door latch and remove the plasic piece it holds.
4. Unscrew lock post.
5. Pop off the Up/Down switch cover and disconnect the wire
6. From here everything comes off at once; Armrest etc.
7. Us a wedge (I made mine by sawing a 2x2) to pop off about 5 or 6 snap type connectors until it's hanging free.
8. At the base of the window there are 4 (I think) snaps that you have to lift the panel out of.
9. There is a heavy wire sort of loop connection that you have to kind of wiggle the panel around to disconnect.
10. That should free up the panel entirely and you can set it aside.