So what’s the problem with getting your Mozilla “sent” file, for example C:\DOCUMENTS AND SETTINGS\UserId\APPLICATION DATA\Mozilla\Profiles\EMailId\blahblah.slt\Mail\email.server.unc.edu\Sent

I go to:
C\D&S\me\AppData\Moz\Prof\jwatt\blah.slt\ImapMail\imap.unc.edu\INBOX.sbd

and in there there were MSF files for email mailbox, except the files are unparsable to my eye. lines look like this:
(EE=3f8246cc)(EF=e62)(F0=1065551696.3f830750382f5@webmail7.isis.unc.edu)

Using POP you typically have another file with all your email in it, but with IMAP the files are on the server. The MSF file is useless IMHO. So you’ll need to pull the email file from the sefver which will take more work, and investigation on how to do this.