Sheldon, you WON'T get a VFR clearance on the ground into Class C airspace pretty much anywhere in Australia. In the situation you mention I would give the Melbourne traffic manager a call (number in ERSA) tell him/her that you have a VFR flight plan in the system, you're getting airborne shortly and request the code. Setting it on your transponder prior to airborne will speed up the identification process (you WON'T get a clearance til you're identified).
And W'rTF you do, don't bust airspace til you've got the clearance
