I'm fairly sure the story you're searching for was titeled "Harry Potter, Veela Mate" and that the autor was dpiloff on ff.net. But I'm not completly sure.
However, when I visited dpiloff's profile on ff.net I couldn't find any of his stories and with the recent "cleaning" there, it's probably sure to say, that they got deleted. That would really be a shame, because I really, really loved his stories and he is one of my most favourite authors.