From my understanding, a hunter can aggro vael and feign immediatly in order to give your raid the buff w/o aggroing him fully.
If this works you can effectively buff/summon food/water and res the dead extremely fast to save time in-between attempts.
If 2 people have the time to log in and verify, that would be great.
Possible positions are in vael's room, in razor room, or by the zone in to be buffed i believe, so 3 attmpts would be enough to prove/disprove what i had heard. I don't have a hunter friend with access to test this.
I am fairly sure it works, I just do not know the exact mechanics behind it. Ihave gotten the vael buff a few times w/o aggro and was able to buff/summon the entire raid w/o consequence to my mana.