Like Clivia, Cryptostephanus have seeds that germinate immediately and regardless of their surroundings as you probably know.

I would suggest contacting Rachael at Silverhill Seeds in South Africa. Ask to be placed on the Amaryllidaceae mailing list. Then when new Species of perishable seeds are available you will be notified and can order. I've done this on a number of occasions and it works well!

Here is a link that might be useful: Silverhill Seeds