The earnings chart no longer shows it, but initially after Hainan became a partner, P was explicitly listed as an excluded fare class and can be found in the http://www.flyertalk.com/forum/alask...confirmed.html thread.

Note that on Hainan's own FF page, they've made changes to earning classes in their own program as of July 1st. P on domestic went from a 0% accrual Other Classes to a 50% Economy Class. It's still a 0% accrual Other Classes on international/regional flights. Are you sure it's a first class fare?