[G4] go to Outlook Express from Mail app

[John Erdman]

For reasons I don't really understand a dear neighbor has elected to go 
back to OS 9.2.2 from OS X. (I think she doesn't like to work in 
classic mode, but that's beside the point.)  She would like to export 
all her Mail, address, and mailboxes back to Outlook Express (Ugh!). 
Can anybody tell me how to do that. I am aware of how to go the other 
way but it's not immediately obvious go backwards.

Thanks,
John