Look over the RFA thread linked in my signature below. I think there are a few of us who have been lucky enough to have babies and a few even caught the spawn on video and posted links (in my thread). If you have any questions about the info there, ask the question there and I'll reply there.
I don't have any secrets to it, I've just been lucky to have three rounds of babies. I think they need to be fully mature, mine are 3" or more in diameter and I do feed them every couple of weeks besides whatever fish and coral food they get from regular feedings of every other day.