I hate to tell you this, but you should have searched before embarking upon the job. I posted several times, not too long ago, regarding the need to avoid reconnecting the battery until the job is completed. The SRS light cannot be reset by a standard OBDII scanner; only a dealer or qualified indy with the Mercedes scanner can reset it.
Link:
http://www.peachparts.com/shopforum/showthread.php?t=169322&highlight=srs+reset
I had hoped my experience would have helped someone here avert having to spend extra $$$, so I feel really bad for you reading that you somehow missed it...