On the e53 X5s that have the adaptive bi-xenon headlights...the outboard lights (as the OP mentions) are the low beam & high beam bulbs...a flap opens when high beams are initiated.
The inboard bulbs are the F-to-P (flash-to-pass) bulbs that come on when the turn indicator stalk is pulled backward towards the driver...and those bulbs can also be programmed to be DRLs.
I'm not sure how it works on the E70 especially since the LCI (facelift) models have the LED AEs that operate as the DRLs. Do the e70 X5s have th F-to-P feature if you pull backwards on the turn indicator stalk?
EDIT: just checked the e70 owners manual...looks like you should have the F-t-P feature, too. Have someone pull backward on the turn indicator stalk & you should see the inboard headlights illuminate...or pull-in or park where you can see a reflection of the front end of the vehicle...then initiate the F-t-P feature. (see page from e70 owners manual below):
{from 2009 owners manual...which would be pre LCI}
