also if you are trouble getting HF on the ground at some communities. Is call up briefing as you are about to start up. You can then give a taxi report to them via phone, that will then activate your flight plan and they will give you any appropriate traffic and then activate your IFR SARWATCH.
The above advice is slightly incorrect. There are numbers in the ERSA, for pilots of IFR flights to call in cases like this. Briefing is in a completely different building (and completely different state if you're controller is in Melbourne), and is difficult for them to contact the operator of the console concerned with your flight.
The numbers in the ERSA are a direct number to the Supervisor I believe it is, at either Brisbane or Melbourne Centre's, and they can easily contact the controller's at the console's and co-ordinate it from there.
Cheers
morno