For the Helo guy, sure you can do your training in OZ then when you get home convert to your home country. Look I maybe going to Belize for the winter to fly helicopters. I know that I will have to convert my FAA certificate to a Belize one. Unless the aircraft is of US registry. You will be able to fly an OZ aircraft you are rated for anywhere in the world. Getting the right to work anywhere is another story. Talk with your Aviation Authority about what you are going to do and what is going to be required for conversion. For example in Canada you only need 100 hours for a commercial pilot in helicopters, while the FAA requires that you have logged at least 150 hours of pilot time, with at least 50 hours in helicopters. You will need to look at your nations regs for the issue of a commercial pilot - helicopter and make sure that you meet all the requirements. You would be looking at a written test and a check ride at tha very least. Its not hard, just takes time and a fair amount of cash.