Golf MK5 - which wire is for reversing light?

Hi

I'd like to install a rear parking sensor on golf mk5 and am looking for the reversing light wire to get the power from.
I have completely no idea which one is the right one to connect even though i've googled a lot.
would you any of you let me know?

Pic of right side of rear light wires :
Downloads


Pic of left side of rear light wires :
Downloads


Cheers,

Get a circuit tester (a bulb and a piece of wire will also do) switch the ignition on and with the car in reverse check which wire has power