Hey, I'm not your customer am I?!! We're in the process of transitioning from NetBackup 6.5 to Simpana v9.
Backing up EV is a pig regardless of the backup product being used. NetBackup's EV agent helps to a small degree because it enables you to create a single policy that backs up the SQL DB, indexes, vault store and system files. However, in reality it just fires off child jobs using the standard SQL and file system backup agents, so it really does nothing to help with backup performance. Therefore there is little advantage to using Netbackup for EV backups over any other backup product.
The best thing to do is read the following EV backup best practices guide and translate the NetBackup terminology into the CommVault equivalent.
http://www.symantec.com/connect/articles/enterprise-vault-backups-best-practice
The important things to remember are:
1. EV must be placed into read only mode, or be taken off-line altogether, before backing up the EV data set. When I refer to data set I mean - Vault store partitions, indexes, SQL databases and system files. Ie, take EV off line, backup each of the components in the data set and only place EV back on line when all have been completed. This is the only way to guarantee the integrity of the backup.
2. I don't recall seeing this in the document, but if your customer is using EV safety copies (ie, once an email is sent to the archive it is not deleted from the mailbox until the archive has been backed up) you must ensure that that the backup job clears the archive bits within the currently open vault store partition. Failure to do so will result in mail boxes filling up! You really only have two choices - backup the open partition using the file system agent with clear archive bit enabled (slow!), or do an image based backup followed by "attrib *.* -a /sub". I have heard of people using the latter, but it sounds a bit dicey to me!
I'll report back here once I have tweaked our environment.