The normal backup that SBS 2008 creates contains all the necessary information to restore the entire server. The normal SBS backup includes the system state data. You may wish to create a system state backup of the machine before you make critical changes to the machine or active directory. The ability to take just a system state backup is not exposed in the GUI interface of backup. If you wish to take just a system state backup you must use the wbadmin.exe utility. WBadmin.exe is a command line utility. You must first open a command prompt as administrator.
The command to start a system state backup is: Wbadmin start systemstatebackup –backuptarget:F:
Where F: is the drive where you wish to store the system state backup.