[ZwickSAN]

I'm trying to replace a standard steering wheel on my '88 Carerra with a Momo. I took the brackets off the back, but can't figure out how the horn "button" comes off. There are some esoteric looking screws that are exposed after the brackets were removed (attached picture), but they obviously require some specialized tool if they need to be taken out.

I'm thinking it just pops off, but I'm reluctant to try that if it doesn't. I thought there was a posting concerning this, but have been unable to find it. Any ideas?

Mick