Grohe Shower Faucet Covers

I've got my two faucets working, and trim all in place except for the faucet covers. They look to be a simple pressure fit, where I push them on to the template "washers", but I've tried pushing with as much force as I can muster, to no avail. The Grohe pictoral installation instruction shows a screw driver coming at the cover from the underside, but that looks to me like the way one would pry the cover off once you'd managed to pop it on.

Am I missing something?