w219 cls fibre optic radio upgrade

[wozmoore]

my 2007 cls 350 has the hk command unit in it. i have an after market dvd head unit which im trying to install. i can connect the new unit to the existing fibre connection via the adapter it came with and the sound works. i believe i need a 5m aerial lead to go to the amp in the boot. my main problem is i cant see a wire behind the old unit to attach to the new can bus connector on the new radio. i want to get the steering wheel controls working, can any one tell me where i can connect the 2 green wires from the can bus adapter. thanks