[CentOS] imap flags on uw-imap

I am talking with a client about moving from CentOS 3.7 to CentOS 4.x and migrating their uw-imap to cyrus-imapd but in the process, would want to do a clean install. This is problematic in that if I want to preserve the IMAP flags for all the users INBOX and other mail folders, I would have to move them to another computer and then use something like imapsync (which I've used before) to copy the mail and all of the folders from the old IMAP server to the new one.

I haven't a clue where/how uw-imap stores these flags to even begin to presume that I can successfully move them (though I suppose I can rsync the /var/spool/mail and the users folders)...does anyone know where these flags are stored?

Craig