Symantec recommends that you perform consistency checks before running a snapshot backup.
See Backing up Exchange.
To configure a snapshot backup for Exchange resources
Create an Exchange backup job.
See Backing up Exchange.
Set default options for the Advanced Open File Option.
For Exchange Server 2007 resources, Backup Exec automatically performs snapshot backups. You do not need to select options for the Advanced Open File Option.
See Setting defaults for the Advanced Open File Option for backup jobs.
Ensure that either the Microsoft Volume Shadow Copy Service option or the Automatically select open file technology option is selected.
If resources that are not supported for snapshot backup are included in the backup selection list, check Process logical volumes for backup one at a time to allow the job to complete with errors.
More Information
Creating a backup job by setting job properties
Snapshot and offhost backups with the Exchange Agent