I'm no expert but I believe they're not the easiest to breed in captivity. The local bird shop to me had a seemingly lovely MM2 for a while who was was apparently an ex-breeder bird who had been 'retired' after inflicting serious injuries on his two mates, and according to the guy in the shop that's not entirely uncommon with this species. I was really taken with him but with a female cockatoo of a more delicate species already in the house I reluctantly concluded that, as adorable as he was to humans, he wouldn't be a sensible addition to the family.
Why do you want to breed them?