Have a 2014 GL450 with a broken 3rd row seat belt clip. The rear cargo cover retracted quickly and when it flew forward it caught one of the 3rd row seat belt clips and broke it off. Figured it would just snap out and be easy to replace. (yea, I know, wishful thinking). Received a new clip today and it appears as though the clip is screwed into the interior trim panel from inside the panel. Any insight on how to replace this clip would be appreciated. Likewise, if I have to remove the rear interior trim panel, the procedure to do so. I am mechanically inclined, but not too proud to ask for help. Thanks.