Aluminum isn't magnetic.

 

They sell magnets with holes in them to bolt them onto something. but I don't realy want to drill holes in my roof to put another roof rack mount closer to the front

 

I think Zasder modified the rack to actually slide the crossbar farther forward and avoid drilling holes and what not. I can't find his thread on it...but he actually has pics showing the drilling and mounting of the lights to the crossbar. Shoot him a PM or hope he posts here