Hi!
I found something very interesting with my DK and dualspec.
1. Go in your primary spec (blood) and switch in frost presence
(you will get +AP from the talent "bladed armor")
2. Now stay in frost presence and switch in your secondary spec
3. Switch back to your primary spec and switch in blood presence!
the +AP you gained from "bladed armor" and frost presence will stay in blood presence!
-Hirb