New trim fell off

[Skunksmash]

How would you go about fixing this? Apparently 3M's adhesive for this trim ain't so great. I don't get a lot of time to work on the truck, and for the most part it sits in the garage. I am fixing it up a good bit before I start driving it on a fairly regular basis. So I hadn't gone in there in about 3 weeks. But then I finally go in, to find that the last bit of work I had done, has come undone. You can see the trim just laying there on the ground next to the truck where it fell off. Rather irritating.

So what should I use to fix the trim to the truck more permanently? Contact cement? And what is the best method of keeping it pressed up against the truck while it dries? Plus the old adhesive creates a lump in between the surface of the trim and the surface of the truck.