2018 CR-V EX. Per a stereo manufacturer I need to remove the trim in the trunk area on the right side over the back wheel well to place an adapter to receive radio stations. I am able to pull from the front edge and the back edge to get a good start, but there seems to be something in the middle that is keeping it secured to the frame. I did find the screws in the pull tab for lowering the seat and the retaining bolts in the spare tire area. But I am still missing something. Any ideas? Also attaching the photo the stereo people sent in case it is helpful.