Exchange 2000 Restore

Restore old Exchange 2000 maibox from Backup Exec old backup

Dear all, We upgraded our exchange 2000 to exchange 2007 sp1 last serveral month and we phase out the old exchange 2000. However, our user would like to restore the exchange 2000 mailbox from the last year. We don't know how to restore it from the old backup tape as the old exchange 2000 already...