Backup of blocks is more efficient than individuals files as you've obviously come to realise. Efficient on time and resources in use to perform the backup. Storing indexes for millions of files is very inefficient and frought with problems. Although you can resort to checkpoints during your backup, so that if the backup failed part way through, say a timeout, you would pick up where it left off.
Things to consider from your info.
Your not a Windows person, but you would require to setup a Windows VMware Backup host under 7.1.0.3
You dont look like you have one in your environment that you could turn one into. So there is that to consider. Additional licensing will have to be considered for the backup host and per ESX host that VM's are on you wish to backup.
So give the VSP technote a go. However, the technote was created in 2005, keep that in mind. (might be some compatibility issues - maybe not)
Recommend you investigate VMware style backups:
It is becoming more efficient to use the VMware snapshot backups using the vstorage api. And this might be a route to consider if you are still using the traditional method of a NB Client inside all your VM's.
Here's a nice document to consider for best practices, shown at VMworld 2012 for NBU 7.1
http://www.symantec.com/content/en/us/enterprise/white_papers/b-netbackup_best_practices_WP_21195951.en-us.pdf
