Fill a store with messages

Hello i'm kind of new in here and i've a question. About the stores. I've 
mannaged to create a new provider in 
evolution-data-server/camel/providers/testing 
i also can get the thing to make me some folders. like inbox, outbox and such. 
The also includes the type and icon. but i don't know how to fill them with 
messages. How do i fill the store with messages?

Thanks in advance.