you'll first have to be authorized to drive a pov, given that's a go, you'll have to have a valid drivers license for that country. then msf course. The license will likely be issued by the post/base you're assigned to, they will also test you and give you study material. The MSF course will have to be taken within 3 years of applying for your license, if not, you'll have to retake the MSF course. Then go back in to the licensing office and get your motorcycle endorsement on it.
If you already have a stateside license with a motorcycle endorsement and have taken the MSF course within the last 3 years, then you'll only need to pass the drivers test (written) for the country you're in. Having said that, it could be different wherever you are going. This is how it is in Korea. This is a good question to ask your sponsor. He/she should find the answer for you.