How can I Insure this?

I have been running a biker charity event for 6 years now, and it goes pretty well I'm pleased to say.
This year we have been offered a brand new motorcycle to win. The dealer says he has done this thing before.
Basically, you get 7 dice, if you roll six sixes you win the bike. The dealer also informs us that this activity can be underwritten/insured.
Does anybody have any idea who I can contact to get more information and an idea of costs.
Thanks
Ali