How to Restore Exchange Mailbox from Older Backup Version

I have installed Backup Exec 2012.  We have been using this for a couple of months now.  All my backups are done through this.

I have a request from upper management to retrieve a mailbox from our April 2013 end of month tape.  It was backed up using Backup Exec 12.

I have loaded it and inventoried and cataloged.  How do I get it to recognize the data off that tape.  The server is still the same server from the backup.

also, I backup to disk before tape.  I did "Duplicate" the Exchange store that I want to a "Disk Storage 0001" area thinking I could do a search and find it that way.  So far no luck.

Help.. 

Thanks once again

Cathy