Hmm, given BMW HK's markup it might be worth trying to order the part yourself and getting an indie shop to install it. The downside being that if it doesn't work you're stuck with a very expensive paperweight.
I'm ordering some stuff from the US, if you want we can split shipping if it's not available in HK without ordering
Also, it's cheaper here:
http://www.bmwmercedesparts.com/part...&siteid=215771