Before you begin, note the Event ID of the alert you wish to change.
ALSO, these steps directly modify the BackupExec database. If you screw up, you may need to rebuild/restore/reinstall the database entirely. To make a backup of the table before you begin, use a Select * Into statement.
Some LockFlags Values:
268435560 - disable everything but record event & SNMP
268435552 - See EventID 58063 - Media Remove
268435528 - See EventID 34113 - Job Failure
268435521 - See EventID 58061 - Media Insert
96 - disables only the job log & respond with options
64 - See EventID 34112 - Job Success
Good Luck & don't blame me if you screw up everything. I didn't test this, i just tried one & it worked...