I just went and took a peek at schematics to make sure this is as accurate as possible (in the event that my memory was bad). It looks like my last post was accurate. The horn relay receives a ground input from the horn button.
The part that will be hinky is dealing with the adapter and however it's slip-ring is configured. (By slip-ring, I'm referring to what some might kinda call a clockspring - it's a metal wafer on an aftermarket wheel hub. It normally has a wire soldered to it to allow a horn connection to be maintained with a steering wheel. On a stock wheel, its equivalent is an electrical connector and 3+ rings/circuits in the slipring, IIRC. It's been awhile since I looked at the back of a stock wheel though.
Anyhow, you simply need to attach a wire inside the cavity that the horn button covers. I've slipped a wire under a mounting bolt that connects the wheel to the adapter, etc to achieve this. This goes to one side of the horn button. Then with a normal steering wheel adapter, there's a wire coming from the slipring (metal wafer deal) up to the area of the horn button; connecting this finishes the wiring.
Do your adapters have a provision for this wire? As Go-stang noted, that's the crux since you cant run wires outside the wheel.
I have all the stuff for the fox laying out so I can take pictures of the 'slipring' and all that if needed. And in a week or so hopefully I'll be removing the 94's steering wheel and can take a look at what's going on inside there.
Sorry to not remember how things are better. If this were for a fox III, I'd be able to give exact wire colors and continuity testing for you to keep your cruise control and everything. I normally just have to check schematics and do lots of meter testing to figure out what is needed though.
This didnt help much - let me know where I was too ambiguous, along with any extra info about any wiring provisions that can be done with your hub adapters.