I kind of touched home with this, but, you use two wires for the audio buttons, the BLUE and WHITE. Blue is the ground wire. As stated above, I grounded that inside the wheel itself along with the black wire for the illumination buttons.
The white wire has to be ran through the roll connector. If you removed the pins from the white connector like I said to do earlier, then ends should look as they do above, and you will be able to slide the white wire right onto the prong inside the roll connector up top. See this photo below. The yellow wire is for the illumination, as I mentioned above.