The part in picture #2, that I refer to as the "ramp", is in picture #1. It is just to the right of the chrome handle housing piece. These "ramps" are spot welded to the car. Drill out the spot welds and then cut along the stainless track to get as much of the ramp as you can.
I suggest you get the two different sunroofs side by side. Open them up, have a look, and all of this will make sense to you.

__________________
a few mb diesels