Grid tie inverters can't work without being connected got the grid, you need the grid for the Inverter to switch on, you cannot run a grid tie inverter with only the PV panels connected .
In this case the inverter needs to see 428 V on all three phases.
As to your question if this can be bypassed with I simple software setting - I don't know as these inverters are not common in RSA but in all probability not.