Early non LED xenons are on dip beam as DRL's along with the tail lights, just like the Scirroco and Polo. It may possible to code it so that the tail lights don't come on, but the chances are that as your car has no specific DRL (like the halogen cars, the .:R or later xenons with LED's) it won't give you that option.
Can you turn them off completely using the indicator down, pull to flash and turn the ignition on and off (or whatever the procedure is)?