Hi Noob -
We currently do not have the Biztalk 2006 Database on the Software Compatibility List, which also means no agent or support exists for it.
I would suggest backing the databases offline if you can afford a small amount of downtime. I have referred a link to the 11d Software Compatibility List of the databases we do support.
Symantec Backup Exec 11d(11.0) for Windows Servers - Software Compatibility List (SCL)
- Jared