That one does send a grower on a bit of a search :) I don't see anything you need to do differently than what you have done.

There are a few mentions of length of time to germinate that indicate some time involved, anywhere from 1 - 6 months.

But, the Royal Tasmanian Botanical Gardens germination database shows (if I'm interpreting it right) seeds harvested and held 7 months before sowing germinated (at a rate of half the seeds sown) in 12 days with more to follow. Temp was approx 60F and seeds were exposed to 10 hours light, 14 hours (night) dark.

FYI - intolerant of both shade and root disturbance, handle seedlings carefully when transplanting.

Thanks so much!

You can find some usefully informations this link:
http://www.ehow.com/how_12094796_germinate-leptospermum.html

Good luck...