Based on the date of your post, I am assuming you have the problem fixed by now ... but ..... to help out other members: I just had my 2000 M Roadster mirror repaired by Scott at Radar-Mirror
. He is located in Frisco, TX.
I live nearby, so I drove to his shop and he replaced the mirror pack in my OAM mirror with a brand new dimming mirror face for $90!
Check out his website. He is an OK guy, and a Bimmer Head.