i think you just hold down the button on the end of the turn signal while your on the display you want to reset. its either that or press one of the two trip reset buttons. i can't remember for sure. try the turn signal button first though.
<img src='http://www.bmw-forums.com/forum/uploads/post-4-1081744190.jpg' border='0' alt='user posted image' />
<span style='color:gray'><span style='font-family:Arial'>2000 323Ci alpine white</span></span>