Hef-
For the pacific fleet all you need is a current licence/ rating. The regulators don't tend to care too much about what goes on out there. The machines aren't alway's registered although they do tend to have some magic numbers plastered on the side. Your crewmens Visa is only a necessity if you don't have a return airfare. I would buy a return airfare as you may not like what you see! Good fun out there but definitely keep your wits about you.
Good Luck,