Actually, the quest is set to work for any TM spell, though I'm not certain if AOE stuff works right for it or not. There's also a message you get when you reach the number of kills you need. If you didn't get the message, some of the kills didn't count, so keep killing till you get a message. Otherwise you aren't killing the right thing.
FGM Ricinus
Logistics Lead
Magic, Sentients Team Member
Cleric Advocate