You can back up the individual documents that are contained in the SharePoint Portal Workspace, which will enable you to quickly restore individual documents without restoring the entire SharePoint Portal Server database.
To back up folders and documents from a SharePoint Portal workspace
From the Backup Selections pane, under Local Selections, expand Microsoft SharePoint Portal Workspaces. If SharePoint Portal Server is installed remotely, expand Remote Selections.
Select the folders and/or documents in the workspace that you want to back up.
Start the backup job or select other backup options from the Properties pane.