I did it!!
I found the parts online and paid a whopping $36 for everything. The shipping is what brought the price up; it was $13.95, the parts were ~$19 plus tax!! Anyways, the holes are under the liner, you just have to put the treenails (plastic clip-in nuts) to catch the screws. You don't have to pull the whole liner off; I just unsnapped the bottom clips, and removed the plastic covers from each trunk arm (not sure the proper term). I saw the holes where the treenails go, clipped them in, lined up the screws, and like that, I was done. No exaggeration, it took me maybe 15 minutes to mount it. The longest part was lining up the screws to the treenails. Once I got one side lined up, the other side was a snap. I'll post pictures this evening of the part #s and the finished product. All in all, very easy to do!