How do I remove seat belts on 99 cavalier?

I need to run wires to the rear door power door locks that I'm installing, and also run the power cable to my amp through the trim that runs on the bottom of my doors. To remove the bottom trim, seems like I have to remove the top center trim (between the 2 doors, next to the drivers head) where the seatbelts attach. But I cant remove that piece, unless I take off the part that adjusts the seatbelt up higher or lower, and I have no clue how to remove it.

Under the black/tan cover on the seatbelt itself is a bolt. Remove said bolt.

I believe that it is a torx head bolt.