There it is! I had some things to figure out and adjust. The distance between the holes in the seat brackets was too short, so I had to expand the rear hole by a couple of millimeters. That wasn't too difficult.
But getting the plug for the power seat disassembled so I could remove the seat belt buckle was quite a challenge. Still, the buckle is a bit too short, so I might get a longer one or an extender for it. Any suggestions?
The seating position is very good, though.
Edit: That's glue residue on the backrest. I had a minor issue with the seat padding...