Jorn, I just happened to have written down the exact procedure to get the cylinder out of my '91 300se - built in Oct, 1990. I bet they are the same.

1. Get a 2 mm piece of wire or rod, about 6 " long or so.
2. Grind a 70 degree angle on one end.
3. Turn key to acc position 1.
4. Insert the wire into the hole/slot just to left of the top of the key (approx 12:00 o'clock).
5. Turn the ground side of the wire inward.
6. Press the ground end of the wire outward to pass over the top of the lock cylinder.
7. Then press ground end of wire inward and push in to unlock the pin.

It's been several years since I did it, but I remember messing with it a minute or two getting the feel, then it popped right out.

DG