Ramset will blow a hole through the foam insulation. I assume this is a concrete wall you are asking about. There are fasteners called "stick-clips". They are a metal plate with a welded spike. The plates are adhered to the wall with epoxy and the insulation is pushed to the wall and the stick-clips impale the insulation, sticking out about 1 or 2 inches. The attachment is completed with a plastic or metal disk pushed down the protruding spike which resists backing off (sorta like an oversized tinnerman nut).