Ok, so I'd like to think I've researched this issue pretty thoroughly, but I've come up with nearly nothing. Please tell me there's a better way to do an NBU backup of a MySQL database than to do an export and then pick it up with the standard backup rotation. At least we can do hot backups to the export, but surely there's a better way......
Sounds like you're hoping for an Agent (like MSSQL and Oracle and Sybase, etc). Unfortunately I don't believe that there is an Agent for MySQL.
Here is an idea that might be a step further for your situation. Setup a policy that allows 'User' backups 24x7. Modify your script that does the MySQL export and add a command to initiate a 'User' backup (using the /usr/openv/netbackup/bin/bpbackup command).
That way, as soon as you export the DB to file, you immediately send it to tape. No waiting for nightly jobs to pick it up!
Use the bpstart and bpend scripts to control the schedule of Mysql dumps. Confiure a dedicated policy for the database dump directory. This way you can send errors to standard output and control database backup failures using regular Netbackup error codes.