Fronius GEN24 export limiting

As it seems that the SPOT market electricity price more often is near zero or slightly negative I have the need to limit the export of excess energy to the grid. This can manually be done in the inverters interface with setting the soft limiting value between 0 - system peak kW.
I have not been able to do this programatically by setting the Modbus registers that I think are involved, mainly 40233 that according to documentation should hold values between 0 - 100 but in fact is 0 or 1.

Has anyone succeeded to programatically control the export limiting programatically in openHAB?

I have done it with a Fronius Primo Inverter - not sure if the modbus registers are the same or not.

I have Modbus Data ‘Things’ for registers 40242 & 40246 and corresponding items Fronius_WMaxLimPct_Value_as_Number and Fronius_WMaxLim_Enable_Value_as_Number

To reduce output, I set:
Fronius_WMaxLimPct_Value_as_Number to a value between 100 & 10000 (corresponding to 1 to 100%)
Fronius_WMaxLim_Enable_Value_as_Number to 1 (to ‘save’ the value)

To restore production,I set:
Fronius_WMaxLimPct_Value_as_Number to 10000 (corresponding to 100%)
Fronius_WMaxLim_Enable_Value_as_Number to 1 (to ‘save’ the value)