1999 Porsche Boxster Horn not working

I bought this car and they put a after market steering wheel on which looks great and I want to keep it, but the horn does not work! I took the wheel off and the wires were not connected so I did and still does not work. On the back of the steering wheel is a brass ring which looks like is a electric conductor and the hub of the steering column a wire connected to the hub. So I connected this to the PUSH for the horn and the other the ground, but doesn't work.
Please if you know can you help me.
James