Remove the trim
get a 4 lb sledge
carefully start hitting the lip and rolling it in (I go from 10 to the 2 0 clock position)
Reinstall the trim (u will only be able to get in a few screws in down low).
Roll it in the same manner as the other, the trim needs to be tight so it sits flush. i.e.- the screws down low hold it in and the rolled metal holds up high.
Not sure on stainles but the sladge should convince it.