You can catch them on dead bait, I remember an old man caught one on a pilchard he bought from footscray market, he had no idea what fish it was, I told him and measured it for him.
But I think live mullet is the best. A lot of mullet from warmies move up and down the Nong and Yarra and Docks. Could be their natural food source.
When I looked for them years ago, I used kind of paternoster but with a long dropper. About 1.5m and 4/0 circle hook, I could've and should've used bigger like 5/0 or 6/0, they have big thick jaw bone. Then 30-50cm to the sinker. Cast the live mullet to the likely spot and wait, and wait, and wait. The mullet can kick a little, when the mulloway is around, the mullet go crazy! Then bbbzzztttt!!
They're not easy to catch. Gotta put the hours and effort. Good luck, you might get lucky.