With
Kanebear's recent publishing of the rules there is nothing to indicate you can't do that. There is reference to single flight numbers between Australia AND Europe, but nothing between Auastralia and S/A.
There are references to the arrivals and departure limitation here:
Code:
113N . 4. 1 INTERNATIONAL DEPARTURE AND 1 INTERNATIONAL
114N . ARRIVAL FROM/TO THE COUNTRY OF ORIGIN PERMITTED.
115N . EXCEPTION - ORIGIN USA - 2 PERMITTED. 1 ARRIVAL-
116N . DEPARTURE MUST BE A TRANSIT WITHOUT STOPOVER.
117N . NOTE: TRAVEL BETWEEN THE U.S./CANADA IS NOT
118N . COUNTED AS INTERNATIONAL ARRIVAL/DEPARTURE.
I would suggest getting a second opinion if possible. If not, perhaps you could start somewhere else?