Installing New Steering Wheel In 512TR HELP!

I'm trying to swap the existing 512TR steering wheel over for a MOMO MOD 78 wheel, but I'm having problems fitting it. When I pull off the leather fascia/cover of the original wheel I notice 2 long cables protruding from each side of it, and 2 cables protruding out of the middle of the boss. All of which plug into the 2 spades (via twin adapters) found on the underside of the horn box compartment which is built into the leather fascia.
On the MOMO MOD 78 steering wheel there are no cables protruding from it at all. And on the separate horn box compartment that comes with it, there is only 1 spade terminal on the underside of it instead of two. However there is a hole where another spade terminal can be screwed in.
How do I install the new wheel taking these facts into consideration?