DI542 you may find that a call to QF reservations bears fruit. I had the same problem with D class inventory on an LA flight AKL-SCL, which I was trying to book under the QF designator (100% mileage bonus for WPs). LA was showing something like J6 D3, while it was zeros all the way for QF. A couple of calls later (the first agent I spoke to wasn't of much help) and, as if by magic, 2 D class seats open up under the QF designator. In your case it should be even easier given that the flight is also operated by QF. I suspect I wouldn't have had this help as a bronze member.