C320 door lock sensor plunger, plunged.

My wife's car has just developed a small problem, Her drivers side door lock pluger located on the post behind the drivers seat has fallen into the abyss. When I tried to get the plastic shielding off to get at it, seemed simple enough, I broke one of the clips. I do not want to break any more and am looking for someone who has the schematics of that area so I can forge ahead with a modicum of knowledge.
All I have to do is puch the switch back into the grommited hole and I am home free.

Help???