Aha, I think I have an idea of what you're looking for.

Basically Blueprints of the electrical wiring throughout your car, am I right?

Ivan, I would try contacting the Mercedes-Benz Classic Center. These guys have all the specialists who can make an old and rusty Mercedes look like the day it left the factory.

Link: http://www.mercedes-benz-oldtimerser...home/home.html

Here's what you're looking for.

Allgemeine Fragen, Ersatzteile und Technik
Tel. 0711 17 84040
Fax 0711 17 83456

More phone numbers below. If you're having trouble with the German (which is unlikely since you speak it well!), there's also an English version.

Link: http://www.mercedes-benz-oldtimerser...ic_center.html

Hope this helps.