well I have no experience with this but I am guessing you need to find the wires that originally went to your horn buttons... and then modify them to fit your new horn button. I don't think the horn goes through the airbag on usdm steering wheels, but I might be wrong... hopefully someone has done this and can enlighten you

edit: what did you do about your SRS system? have you disabled both sides or what? Just curious. I think we need a wiring diagram