The Advanced Disk Based Option is used by very few people. Why Symantec charges for that feature is abbsurd, when half of it doesn't work reliably at all.
Basically it's used for two things. SAN based snapshot backups with a compatible SAN storage device, or for Synthetic backups. It's the latter feature that has been broken in multiple versions of BackupExec.
I do not think this is the option you are looking for. And can you clarify what you meant by "Diary Backups?" Bad spelling I can figure out, that word used is just confusing.