NetMail 3.1 -> GW 8. imapcopy?

[toforama]

We have just recently purchased licenses for GW8 and I am planning the migration from NetMail 3.1 to GW. I was looking around for how to migrate the mail over and even put in a ticket looking for assistance, and I was referred to imapcopy as the tool to use by a tech at Novell and I see references to it here too. Looking at that documentation, however, I see it refers to setting up a .cfg file with everyone's usernames and passwords, but we are looking at migrating almost 350 people and I frankly do not know all of their usernames or passwords. Is there a way I can force the issue using the admin account (which I doubt if this just relies on IMAP but it's worth asking) or would there be some other way to migrate things smoothly (if not easily)?

NetMail uses standard mbox text format to store mail, for what it's worth, so I suppose the right tool could just read it through as well.

Thanks in advance for any assistance anyone can give!