I am swapping 2007 F350 front facia onto my 1999 F350

Headlights, grille, complete bumper.......

I'm having trouble getting the upper (painted) "pad" attached to the top of the bumper.....the tabs that stick through the bumper from the energy absorber within the pad just won't come far enough through to lock in....

I'm thinking about leaving it all in the sun for a while then try.....

Any suggestions?? Thanks!