Part Number - Light Assist tunnel switch

I might have a go at retrofitting this if its not something my dealer can do.

Has anyone got a part number for the light assist switch?

If you've got one installed, the part number is on the switch which can be easily removed using the instructions here.

Oh - and is there any way of telling (before obtaining the switch) whether this is going to work or not? I have nine wires going into the back of my current (standard) switch and have got the rain-sensing wipers and auto-dimming mirror options factory installed.

Thanks,

Ross