Not sure when they'll actually take over but, Jetstar engineers have from Melbourne, Sydney and Brisbane (and OOL) been doing (and are currently doing) A330 training as we speak.
Whether or not they will just do transit and overnight checks or services such as A checks (like to know where they'll get a hangar and tooling for such work? No doubt JQ management would have already thought all this through?) is not clear.
JHAS could throw their hat into the ring for the A checks but, it would seem ridiculous to take that away from Qantas who are still tooled up for and required to do the same work on their own A330's.
And let's not forget, all this trouble for an aircraft that is supposedly only filling the gap at Jetstar until the 787 arrives. It will then be returned to the mainline fleet.
If I didn't know any better, I'd say the left hand doesn't know what the right hand is doing in QF/JQ management. Either that, or in advance of imminent QF engineering EBA negotiations starting again, QF are trying to insulate JQ international from any industrial action that might occur (pitting QF and JQ engineers against each other) in the course of such EBA negotiations such as in 2008.
Interesting few months ahead in Engineering spheres within the Qantas group.