Once you locate the backup data, you can restore an email folder by restoring
/home/e-smith/files/users/<username>/Maildir/.FolderName
Note that email folder names start with a ".", making them "hidden" from normal directory listings.
The easiest way to restore individual emails would be to restore the entire original email folder -- but to a new folder name. Then the user can fire up their email client and grab the desired emails.
Once you've restored everything you will need to
chown <username>:<username> /home/e-smith/files/users/<username>/Maildir/*
I've also seen some discussion on the forums and in the bug tracker indicating that you may need to delete dovecot.index* in each restored email folder. Basically, do this if you can't see any emails in the restored folders.