I did this, kind of. I got the button (and console with more switch holes), and connected the antenna signal from the radio and the antenna wire to the button, thus controlling the power signal feed via the button. I don't remember if the button needs +12v itself, but I did connect it to the illumination terminal behind the ashtray/radio.
This works, but not fully as Mercedes did it with several different height settings on the antenna. But I'm only interested in being able to control the antenna to be either up or down.
The way I connected it, the antenna goes up automatically when the radio is on/car starts as before when the button is in top position. If the button is in down position, the antenna stays down. Of course I can press down on the button when the antenna is up, and it goes down, and the other way around.
I think it works really well!
BTW - to get it working with the different stages, you need an early antenna with 5? connections on, and then either a harness (if available) or make one yourself that runs to the antenna button.