Hi Kaustubh,
Please try this I am sure it works
1. Create anonymous user account with exchange mailbox
2. Do not hide it from GAL
3. Create exchangeservers.txt file in EV installation mention ip address of Exchange server in it
4. Reset EV service account password from domain controller
5. Logon to the EV server as the VSA
6. Open the Vault Admin Console
7. On the Directory container, select Properties and click on the Service Account tab
8. Reset the password for the VSA, or click Browse to change the service account
9. Click OK when the next window comes up
10. Restart all services
11. Open command prompt on EV server
12. Access to EV installation folder
13. Run "CSCRIPT" as given below
cscript owauser.wsf /domain:<domain> /user:<username> /password:<password> /exch2003
Please let me know in case of any issue
Regards
Abhijit