How do you grow dieffenbachias from seed?

[Walter Turner]

I would like to grow dieffenbachias from seed. Although I have a number 
of varieties, at least one of which produces pollen, I have never got 
anything that looked like a mature seed.
How do I recognize a mature dieffenbachia seed? Why do most of my plants 
produce no visible pollen? If I do somehow get a seed, how do I 
get it to germinate and grow?
Thanks for any help.