Opspecs B055 covers Polar Ops. The best source of information for this issue is AC120-42B, Chapt. 6, which was written after the Polar Ops article published by Boeing. Also requires B040, Ops in the NCA/AMU as a part of the application process.
Operations in the Polar region typically require a validation flight by the FAA. Since there are very few Nav Specialists in the FAA (maybe less than 4), you need to get name on the list well in advance.