To restore a single user's Mailbox or folder is currently only possible in VPOP3 Enterprise, and requires a second PC to act as a temporary VPOP3 server.
You need to:
-
Configure your email client to access the temporary VPOP3 server using IMAP4, as well as your normal VPOP3 server
Use your email client to copy the messages from the relevant IMAP4 folder(s) on the temporary VPOP3 server to the normal VPOP3 server