Planchonia careya is a tree species in the family Lecythidaceae. Common names include cocky apple, cockatoo apple and billygoat plum.
Not something I have ever come across so sorry, cannot help. Think you would need an Australian member to answer this one.

No specific info on the web about how to grow from seed, but Fair Dinkum seeds might be able to tell you - they do have these seeds listed in their online catalogue, although none are available currently, but that might mean they could give advice on how to grow them.

This link

http://anpsa.org.au/p-car.html

suggests it's easy to grow from seed, but doesn't say how.