Since the developers of Bacula prefer to work with Fedora and Suse, bacula administration tool (BAT)'s compilation and installation it's not too easy to do on CentOS, a conservative distribution.
Download the source rpms for bacula and bacula-bat from sourceforge.net
Install few development packages required by bacula
Compile the bacula package with sqlite database engine enabled
Install few packages required usually by Qt compilation, Qt being used by bat, bacula administration tool
Adjust /usr/src/redhat/SPECS/bacula-bat.spec to include some settings specific to CentOS. I've modified the file directly. Below is the .diff, and the full .spec file is attached at page bottom.
Compile the bacula-bat package
If nothing wrong happened, in /usr/src/redhat/RPMS/<your_system_architecture>/ should be located the new .rpm's
CentOS 5.4 Bacula 5 RPMs
Next: Bacula 5 RPM Packages installation