I've recently booked a load of these. WLG-SYD with Jetconnect for QF was fine via the UK call centre.
ASP-AYQ-ASP with Qantaslink operated by National Jet Systems not so. The UK call centre point blank refused to do it, even though I explained that it was possible, and went through the process as described by someone else (probably on here). Apparently it shows on their system as a codeshare on now OW metal (apparently a quasi-codeshare, I've discovered from my reading?).
Anyway, in the end, I gave up and called the US call centre, who did it no problem!