I assume Darren is suggesting ...HKG-KUL-HKG-SYD... because I don't think any of the OW airlines fly directly KUL-SYD (hence the backtrack to Hong Kong). However, Singapore is less than 200 miles from KUL and you can fly QF or BA from SIN-SYD. Perhaps you could drive to Singapore (not sure how feasible that is) or find a cheap Malaysian Airlines flight - such a ticket (on Malaysian or Singapore Airlines) is currently $58. I assume - but do not know - that a 'break' (i.e., non-contiguous legs)in a OW mileage ticket is allowed, given that the award is miles-based.