So, four round pads to limit compression of the mounting surface, one locating dowel, and TWO extensions which would index with holes in the pad, which would then be melted to secure the trim pieces to the inner side of the panel. I suspect the 3M double-sided tape might work better, but in a roll in the u-shaped areas rather than on the flat areas.
Alternative would be to use some very small screws, drill small holes in the two "heat/melt" towers, then put some thin sheet metal for the screw to screw through, and carefully attach them from the backside of the panel. Being careful to only SNUG the screws.
Happy Holidays,
CBODY67