Unless part 61 specifies that the instrument time must be completed in a GA registered aircraft, then yes, you can do the instrument time in RA-Aus. It's simulated anyway and not in cloud, so ok for RA-Aus, unless your school is one that goes under IFR for the practice 2 hours of instrument work.
In reality, there's no harm to be done by heading back from the training area in RA-Aus under the hood - it's good practice regardless of aircraft type and registration.
Of course, there is an assumption here that the aircraft if appropriately equipped, as many are these days.