You can do it manually:
1. Open the VAC (Vault Admin Console).
2. Expand Archives => Exchange Mailbox.
3. In the right hand pane, select the user whose vault is to be accessed, Right Click and select "Properties".
4. Click on the "Permissions" tab.
5. Click on the "Add" button and select the user(s) and/or Group(s) to add to view this vault and Click "OK".
Or use EVPM
http://seer.entsupport.symantec.com/docs/321592.htm
regards,