From BCCD 3.0
BCCDv3 -- Configuring and Customizing
Saving your work to persistent storage is not done by default. This is due to the "unknowns" of the environment on which the BCCD image is ultimately run under. Different disk layouts, SCSI vs. IDE, different network authentication protocols, and other aspects of the local environment make it very difficult to provide an all-purpose storage scenario.
That being said, it is quite easy to access remote or local files, and to store your work so that you can access it outside of the BCCD environment.