No need to do anything special to attach the Skybox to the OEM racks. Worked fine. I did have major issue with the OEM clamping system and locking mechanism that I posted in the OEM vs Thule board -->
http://x3.xbimmers.com/forums/showth...light=oem+rack. Ended up destroying the OEM rack trying to take it off.
Yakima still doesn't appear to offer a foot that clamps to the flush rails, so I ordered a Thule Aerobar from RackAttack, which seemed to offer best price for the overall system (I paid $382 for the ARB47 bars, 460R feet and 4023 fit kit).
Arrives tomorrow so will see how that goes...has to be better than the OEM.