You could try to book the Air Pacific segments to and from NAN under the QF and AA codeshares and see if you get BA credit that way (I think you would need to route this as SYD-NAN-LAX rather than going via AKL). Officially the oneworld rules state that codeshare flights under another oneworld carrier are only valid for mileage/status credit when operated by another oneworld carrier (e.g. QF flight number operated by AA). However, apparently some people have reported getting credit when trying this.
Overall though, I think Darren's suggestion is better. Particularly with respect to flying from SYD to LAX on QF. More mileage and guaranteed status credits.
[This message has been edited by mgm (edited 05-14-2003).]