I've talked to a few dealers and they will not lower it VIA the DIS due to common air suspension malfunctions on our X5's.
HOWEVER, I have worked with a local BMW performance shop in developing a part that will allow us to lower the air suspension. I've been testing it since July and will finish the final details in the next week or so.
Expect a post/thread with more information shortly...

Here's a teaser picture of my 4.8is lowered VIA my part.