Priest PI mindbinder

hey, i had a macro that do for me the pre-burst, and with the double now a things, i want to pi the mindbinder… The macro is something like this :

/castsequence reset=30 Dark Ascension, Mindbender, target [harm] Mindbender, Power Infusion, targetlasttarget [help], Unholy Nova

but from what is read, it’s not possible with wow macro, so i try here if someone have a solution ^^
Thanks you, and sorry for my poor english