The FAQ on Emirates agents website specifically states that one could book EK codeshare flights on QF metal either online, through the TA or with EK direct.

http://www.emiratesagent.sk/11076786

I rang EK to add domestic segments to my SIN-MEL ticket that I just bought and after a good 20 minute wait (checking terms/conditions) the very friendly chap said they can not sell individual QF domestic segments (as separate tickets) or have them appended to the international ticket. He also said that I should call QF and book those segments as EK coded flights, something I thought of as weird.

Am I missing something?