ya its detailed in the thread i linked to. Aux light:
LED light options
Don't think that would provide enough power to work with the VSL 4500 lumen headlight...I may just add my own rechargeable Li-Ion battery pack on the back of the light itself and just bypass all that. The only reason I want a light on it is to compliment my fake license plate to keep cops off my back when I do quick jaunts to my local riding spots.