Restore e-mail

In Groupwise 5.5 how do I restore a particular user mailbox? (He accidently deleted some important e-mail)
I tried re-build the user database but it just brought back junk.
My last backup of the Groupise server is 3 days old and for sure the e-mail that he deleted is on the tape somewhere.
Can you list steps by steps what file I need to restore from tape and if I have to do anything in Netadmin?

thanks