well i played around with this, apparently <p0>(which is yourself) through to <p5> work to state who is in that party slot but it doesnt work for targeting an action on them.
/action "Cure" <me> works for casting on myself (just make sure i have AOE on)
/action "Cure" <p1> doesnt work
mind you "/p Hey <p1>" shows up as "Hey Playername" in 2nd party slot.
Not sure why they would allow <p1> to work enough for grabbing the player name but not for targeting purposes.
Call your Mom, She misses you.