Figured it out. I put a screwdriver into the back and gently depressed this little bracket that is designed to hold one of the wires for the horn button. It came right out. I had emailed gullwinggirl earlier and she only got back to me after I figured this out... and said specifically not to use a screwdriver as I could damage the wheel button and then I'm SOL. Good thing nothing happened. Advises using a wooden spoon handle or something similar. In case anyone ever comes across one of these wheels in the future, well, now you know!