[Biturbos4] Trailer hitch wiring

[DocWyte]

Well, I've got a tire trailer that I plan on using at track events and 
I've picked up the Da'Lan hitch to put on my S4. 

However, how do I wire up the trailer lights to the car?  I've searched 
AW and while there are plenty of people who've mounted the tow hitch, 
there aren't any posts on the wiring.

Do I need a convertor box?  Can I just tap into the rear tail lights, or 
do I need one of those kits that draws power from the battery?

TIA!