I tried posting one of my threads on the issue . If it does not take you there, let me know.
I found the most difficult part of the job by far, was getting the right parts...
As I've written before - MB has changed the seals and holders for the injectors on these cars very often.
Perhaps every year. Once you have the parts it is very straight forward. Good Luck.

http://www.peachparts.com/shopforum/showthread.php?threadid=28432