Try booking using AA, they tend to get this right while BA and QF do not. You can phone the AA RTW desk, or contact the AA office in Sydney (there is one, despite no AA service to SYD for 20 years now). It is on the North Shore (listed in phone book or on the AA web site). I am 90% sure that you can get this ticketed using AA but they would be more interested in helping you if you had an AA sector in there somewhere.