Horn wiring with blocked hollow shaft

[rhoffa]

I am working on my '39 pickup and I have a complete steering box & column assembly out of a '40 pickup along with a banjo steering wheel. My plan is to keep the banjo steering wheel, the hollow center shaft and the column tube, but not the steering box. The bottom end of the hollow shaft will require a coupler (3/4" round x double D) then some double D bar with another coupler to hook up to the power IFS front end I plan on using. My question is how do I wire the '40 horn button if the end of the hollow shaft is closed off by the coupler at the bottom of the hollow shaft? With the setup described I can't use a horn rod, which I don't have anyways. Also I plan on using a light switch in the dash like a '40 model, so no concerns with that wiring.....yet.