Disabling Stop start with software changes is done by "tricking" the system into thinking that all criteria are not met for a stop/start. eg battery too low, so changing that threshold.
In my opinion it is better to just install the adaptor piece ( from Aliexpress etc) that connects in line with the switch on the dash. That then allows the Stop/start to still work when required, but remembers whether active or not rather than always reseting it to active each time the van is started.