A word of warning to anyone planning to do this retrofit on their 2007 - the MDM switch panel is very hard to find since it is technically only a 1 year production part. That, accompanied by the fact that it only came in manuals makes it even more elusive. A new one can always be purchased at the dealer, but it will set you back ~$315
However, I think I may have found a coding workaround in the DSC which will allow you to disable the DSC again but use the SMG DSC button instead.
Working on it now, will report back.
So, there is no way to code the DSC to look for the other old style DSC switch. The coding flag can either be set to SMG or HANDSCHALTUNG, but switching to SMG also enables the DSC to start looking for the SMG messages on the PT_CAN including the yaw rate sensor. LOTS of error codes and check control messages and no start off assistance anymore. The DSC button DOES work, but I don't want to have all the errors just to be able to disable DSC.
On to plan B:
In the midst of brainstorming all of this I had a hunch....why not just re-wire the DSC for the old switch? Well, remember earlier in the thread where I explained my lucky malfunction of the MDM automatically coming on when starting the car? The DSC for MANUAL cars looks for the DSC switch signal on the same pin as the brake switch signal on SMG DSC cars....
This is DSC with SMG cars.....brake switch signal is going to pin 4. DSC switch signal is going to pin 41.
That's DSC for manual cars.
DSC module is listening for the DSC switch signal on pin 4. Because I haven't changed any wiring yet, my brake switch signal is still going to pin 4. DSC is seeing my brake switch signal and thinking its the DSC/MDM switch signal, therefore turing on my MDM when I press the brake pedal.
They must both be a 12V on/off result based on status. Only weird thing is the MDM light dos not turn on/off as I press/release the brake pedal, so it must be doing some redundancy check or something.
If you're a 2007 converting from SMG to manual, you need to move pin 4 on your DSC to pin 30 to move the brake switch signal to the proper place, and open pin 4 for for your DSC switch if you want to use the old button in the event you can't find an MDM switch panel. Then simply swap pin 41 to pin 4 for the DSC to recognize your old DSC switch