Speaker Count Coding for APS 30

Hi!
This time, it's not about a VAG control unit, but about a radio from the company Becker, specifically the APS 30 (BE4715). The radio is equipped for 4 speakers, but the coding for that seems to be incorrect. The fader is also not displayed in the menu. My question is, how can I recode it most easily? Since the radio, in its APS 30 version, is actually intended for DC vehicles, it probably can't be recoded using the StarDiagnosis system for DC vehicles, right? Are there any ideas on how to do this?
Thank you in advance...
Dirk.

The easiest way is to turn off the radio and have it reprogrammed at a DC workshop.

I would be interested in seeing a photo of that.