AS you can see from my post https://www-secure.symantec.com/connect/forums/audit-report-archived-items-access, I have trouble to using the audit report to find the usage of my evault and I had another problem the size of the EnterpriseVaultMonitoring(VaultDeva4.mdb) database, so I purpose the following:
When instaling and configuring Enterprise Vault Reporting/Audit the wizard ask if we want to monitor the Enterprise Vault Service Account.