AA has an office in Sydney (80 Clarence Street, level 8) so the easiest would be to make the reservations with the AA RTW desk and then re-issue at AA. You could also get QF to do it, but it is some work for them and they may refuse if you don't have a QF leg. In case you are wondering why AA has an office in Sydney (I certainly was), it is a legacy of the days when AA flew to Sydney a dozen years ago.