One of two ways. There may be a small indendation in the plastic horn ring cover itself. Use a small screwdriver and pop it off. Or there may be a hole on the back of the steering wheel. Stick a rod or even a screwdriver through this hole and push it off from behind. The cover is only hel on with a spring clip on either side.

Are you aaware of the ponton mailing list at http://autos.groups.yahoo.com/group/ponton/. Over 300 ponton owners hang out there. Great bunch.

Len
'59 220S Cabriolet