I recently went through this same exercise to get the aftermarket Hirschmann I got with my '86 560SL to work. It was in a box in the trunk. I guess no one knew how to hook it up, so someone stuck in a fixed antenna, one of those horrible looking rubber things....anyway, I digress.
First of all, I assume this unit of yours has the standard 3 wires: 1 ground, 1 constant (actually, ignition switched source) 12V +, and 1 12V + 'trigger wire', meant to connect to the head unit (radio, tuner)? Wire color isn't terribly important, as the unit would have instructions clearly identifying these 3 wires. Same goes for the wiring diagrams, more work than it's worth to analyze and find the 3 you need.
You picture only 2 wires. I'm sure that there should be a third, or maybe the antenna motor ground is through the body metal connection (doubtful)?
The simplest way to connect the antenna is to identify which of the wires in the Mercedes plug go with the 3 on your antenna, whatever the color (except brown). A Mercedes brown harness/plug wire is, of course, the ground wire. (But you knew that, right?) Most antenna ground wires are black, I think.
Now you need to find the other 2. Get a multimeter, or a 12V test light, and find which one is dead with the ignition 'off', but has 12V when it's 'on' in both acc and run positions, key positions 1 and 2, regardless of whether the radio is on or off. That will be the constant 12V source on your antenna.
Finding the wire to connect as the trigger wire can be done from the plug end in the trunk the same way, except that now you want the wire that is 12V + only when the radio is 'on', and goes dead when it is 'off'.
The complications in all this arise partly if you are connecting a stock Becker with the antenna height switch, or an aftermarket HU which has been wired to the switch. In my experience, this switch is best ignored if you want to leave it wired in, or cut the thing out of the circuit and use any wire not already used in that plug to connect to your HU's trigger.
You'll probably need to go into the back of the head unit and find the trigger wire for the antenna. You don't say what you have, so I'll assume that it's not a stock Becker, but some newer aftermarket unit. These will identify the trigger wire in the instructions, or on a sticker on the top, usually blue. That wire can be connected to an unused one in the plug, for convenience. Just find it where it goes into the switch and use it.
Once the plug wires have been identified, you can either obtain a standard MB male plug and fit your Hirschmann wires to it, or just cut the plug off and attach mating bullit connectors to the wires you need. There are few people, if any, out there that will care to re-wire an old Hirschmann with the switch-compatible circuitry to this plug anyway, so I'd just cut off and be done with the stupid dash switch.
Hope this helps. Post back results or Q's and we'll be glad to assist....
PS: I just noticed your post dates. Have you been waiting for help all summer?