We have SharePoint 2003 as well, and my assumptions were the same as all of yours - that I could backup and restore individual documents or document libraries. It took a week's worth of emails with tech support before coming to this haulting conclusion: You can't do document level backup unless you UPGRADED from SharePoint 2001 (web folders) and kept the web folders instead of migrating into the SQL based structure of SharePoint 2003. I reread the documentation for BE 10 and noticed that the components that can be backed up for SharePoint 2003 are specifically:
Document Libraries (Web Storage System-based)
- Individual documents can be backed up from and restored to Web Storage
System-based document libraries, or redirected to file paths.
After further inquiries, I was told by a Symantec storage rep that "brick level" (document and document library) based backup would be available in the next release after 10d, probably 11.0.
Needless to say, I was upset that it wasn't more clear in the documentation.