Write of values back to Gen24 not functional

[pipsoft]

I was able to understand and get most of the code going. I receive weather data, have values in the DB and I'm connected to the Gen24 able to receive values. But it seems I cannot write back value changes to the configuration registers:

Current chargeStart loaded from db: 2022-03-07 10:00:00
Is charge currently paused (0=no,1=yes,False=NotSet)? 0
Changed maxChargePercentage from: 10000 to 0.
Battery Stats: {'Battery_capa': 65108, 'Battery_SunspecID': 124, 'Battery_SoC': 570, 'Battery_Status': 4, 'BatteryChargeRate': 5120, 'BatteryMaxDischargePercent': 10000, 'BatteryMaxChargePercent': 10000, 'StorageControlMode': None}
Battery Stats: {'Battery_capa': 65108, 'Battery_SunspecID': 124, 'Battery_SoC': 570, 'Battery_Status': 4, 'BatteryChargeRate': 5120, 'BatteryMaxDischargePercent': 10000, 'BatteryMaxChargePercent': 10000, 'StorageControlMode': None}

"Wechselrichter-Steuerung über Modbus " is enabled. Something else, that I'm missing?