Get in touch with a customs agent, they'll give you the complete gen.
The best advice right there...
As regards importing from Indonesia (or any other nation) the only way you could make this legal would be to officially import the boat into Indonesia or wherever first, and then re export to Australia.
I'm not so sure about that, TD. Could be wrong, but I'm led to believe that, if you buy off-shore and sail it back over some time, they based the fees on the original purchase price in whatever currency it was bought in. ..and if it was bought more than 12 months ago, they asked for a valuation and based the fees on that.
I guess, technically speaking, if you buy a boat in, say, Europe, and sail it to Indonesia, then it would be viewed by the Indonesians as a visiting European boat sailed by someone with a tourist visa..