Well done!!
AFAIK.. The multifunction steering wheel works via 3 wires to the cluster as it does with the clk,not sure if this is for updated cluster only?.. You would need to install the 5 wire steering angle sensor to get the extra wires. the command then runs over a CAN from the cluster.
Multifunction wheel was to allow control on the cluster as well as features on the stereo, hence why its wired to the cluster.
Did your command come from a pre-update w210?...if so i'm not sure how you would make the steering wheel connect without CAN.