Warning Problem resolved
As i read posts in this forum, i read and this for convert an E90 with Halogen to Xenon Headlights.
I read for a problem with the warning message of ECU.
As i see the last post was before about 1.5 year, and i don't know if this problem resolved, if not, a cheap solution (about 20.00USD) is to install a warning canceller between the OEM ballast and the cable who's going to ballast. Not to cable between Ballast and D1S Xenon lamp.
In the future i'll post some photo's from my BMW's Headlights.
With the solution there isn't a warning message or flickering etc.
It's very easy and much cheaper from buing a custom harness, you can find a Warning canceller in Ebay. I've make my convertion before 2 years and till now i don't have any problem.
Sorry for my english.