If you are willing to do a little more work you can have a permanent, 3 button homelink unit. About the hardest part of this is the mounting of the homlink unit. I used a 5 min epoxy for the unit and some 3M trim tape for the cover. All Pics come from DaveZ's thread - Thanks
http://www.bimmerfest.com/forums/sho...d.php?t=226233
I did this and wired it to the cigarette lighter since it is right there. And if you are worried about cutting holes in a panel - dont be. This panel is under ten bucks to replace. PN 51459128397
Power & ground pics:
Pull the ash tray, unscrew and remove screw and remove ash tray unit.
The only real PITA is keeping the cover on and getting the push buttons to contact the homelink electronic switches.
Attachment 511560
For the cover I used 3M trim tape. Google "3M Super Strength Molding Tape PN 03609". You can find it at Wal Mart Auto Zone and Amazon.
To elongate the Push buttons I glued small pieces of wooden dowel (wooden Q-tips) to each of the buttons. Something plastic would probably be easier but it worked for me. You do need to grind down the ribs in the cover where the Homelink will mount but this is still too thick to get the pushbuttons to contact. In the link others have dealt with this issue by thinning out the cover. Looked like too much trial and error to me.
Finally to program the Homelink unit use the pdf.
homelinknr.pdf
Little more work but you never lose this GDO, it never runs out of power, and it looks good. The only thing I dont like about it is you really cant see it unless you go looking for it - its such a clean install I wish it was visible.