Donít know about Fiji but I know a guy that did Vanuatu to Oz in a Jet Ranger the long way.
Port Vila to New Caledonia, Solomons, PNG (last stop Daru), Oz (first stop Horn Is).
Donít now if it helps but thatís how they did it. The machine had Pop-outs and a lot of extra bits and pieces for the journey which was said to be one of the best they had ever completed, sains for the long over water boring bits.
The last option would be to piggy back on a passing freighter.