If the flights aren't showing on the Qantas website you can always check on the British Airways website. (You'll have to create a free account using an overseas address.) Most oneworld flights show on there, and if you can't book them on the QF website you can then call the Qantas call centre to book. The service fees should be waived if it can't be booked online.
Case in point:
I used my Qantas points yesterday to book a LAN flight from Lima to Cusco. I wasn't able to find anything on the Qantas website, but there were plenty of options showing on the British Airways search engine. I called Qantas to book and all the flights showing on the BA website were available. I was charged 10,000 points plus around $14 in taxes. The phone service fee was waived. I was pretty happy with the outcome.