well, now I know exactly why this doesn't work: In the underlying "DataModel" - which is an exact copy of our primary DataModel - the month_names are set to german formatting in that SET command.
=> I have included hints that whenever anything in the primary DataModel is changed, it has to be copied anew
<=> That way I fear that just replacing that SET command would not help me for long, the next time the primary DataModel is copied over, it would be reset.
=> Putting a particular SET command in the qvs file and resetting it afterwards would be a good solution.
I have now found a way: I simply DROP the calendar_table from the DataModel - where I am not sure about the month_formatting - and then LOAD it once more, so I know for sure that it will be using the month_formatting I have specified in that particular app.
Still, doing that right there in the qvs file would be the more elegant way.