To clarify about what I meant about the lack of a horn-button on the hand-control: The CAN Bus is essentially a network that all of the various switches and knobs interface with. (CAN stands for Common Area Network, if I recall correctly). There is not a separate wire for each power-window switch, for example. The power-window switches "talk" to the CAN Bus -- you press the "driver's window down" switch, and that switch sends a signal out on the CAN Bus, which the body-control-module hears and then sends a signal to the window motor to actually roll down the window. There is no direct wire from the power-window switch to the window motor -- unlike in old cars, where you literally had hundreds of wires running to and from every switch in the car. This CAN Bus stuff sounds overly complicated, but it saves literally thousands of feet of copper wire, which is quite expensive and heavy. The horn button on the steering wheel is the same -- when you press the horn button, it sends a signal out on the CAN Bus that the body-control-module 'hears', and it then sends a signal to the relay that controls the horn. There is no direct connection to that relay - thus, there is no wire that I can tap into in order to beep the horn with a momentary push-button. I would have to run my own wire to that relay, which would involve messing with the factory wiring harness, and I'm not about to do that on a car that's still under warranty. :-)
Thoughts on like buying Amazon hand controls and trying to install yourself.
@Dabzdiggler