Don't be put off by previous poster, I've been in the same situation so can speak from experience. It doesn't matter where your employer is based, it could be Adelaide, somewhere else in Australia (think national corporations like banks), New Zealand or anywhere in the world (think global businesses like Apple). The one thing you will need when applying for 887 is a letter from your employer stating that they sanction you working in South Australia, preferably giving your home address as your place of work, and also stating your hours of work and salary. If you can get that then you shouldn't have a problem.