DMXPreset=xx does not work in m257
PresetToCuelist=xx does - I just tested it.
I just tried it in m311 (custom version) and 'DMXPreset=xx' still doesn't work...
but PresetToCuelist=xx does...
Please try either command - and let me know..!..
The built-in help file is out of date and refers to features in previous versions - not all of it is correct:
This is a screen shot of the help file built in to m257 and m311...