Same issue with that antenna plate - take a look at it from the side and you will see the incredibly tight gap which the lip of the case needs to slot into. I assumed it simply butted up against the case, but no.

I used a big paper clip as suggested here, putting in one screw and then lifting through the perforations while applying a little pressure to the plate. Turned out there was one point misaligned and after a few tries it popped back in.