Alright, I've got another issue I need help with!

The lower body trim on the passenger side of my '80 450SL has been coming off in the middle, so last night I tried to take the whole thing off to get an idea of how the trim is attached to the body. I was able to unscrew the front of the trim (in the front wheel well), but when I got the back I couldn't figure out how to detach the mount that holds on the other end of the trim.

In the picture, I have circled the area I'm talking about. Can anyone tell me how that particular clip is attached to the body, and how I can detach it to remove the entire trim piece?

Thanks!