22K
In no way being smartarse but your position is somewhat convoluted in a number of ways, only suggestion is it's well worth to go to two international accountant businesses and pay their fees out of your own pocket - then compare their advice...and proceed as you see fit.
Make sure you have thought about problems you perceive and ask questions - get your $500 plus worth out of your first consultation from each.
Dom's 100% correct IMHO, some believe they don't have to pay tax anywhere in the world, has been disproved over last few years as at least a couple of OZ have been caught up for, at least, discussions with tax authorities.
Also bear in mind that the AirJapan deal is the ONLY contract in Japan that doesn't pay tax, never has, probably never will: to be corrected but I believe all other potentials (Vanilla, Peach, Jetstar Japan, skymark? etc) pay japanese tax after the event - Japan is a dual tax country for a hell of a lot of countries so paid in japan generally covers most other countries...other than the USA so I hear...but WTF would I know??
Best of luck with your endeavour's.
