I based my answer on a question that was sent to FFG sounding like this :
Skull Icons on Tide of Battle Cards
If the final (victorious) attacking unit was removed by a skull icon on a tide of battle card, would it be treated the same way as the Arianne card (in that the attacker would have no units to occupy the area, but would still count as the winner, and would remove any order tokens or power icons from the embattled area)?
"This is correct. Even though the area is now completely empty, the winner still resolves all his effects as normal."
This question among many others were sent to FFG and can be found on this site : http://boardgamegeek...ponses-from-ffg
This question is answered before the FAQ was published but having read the FAQ now it doesn't seem to me that anything there refutes this answer (although it is not directly answered there). I can only understand this in a way that the power token is removed.