The backup wizard in the SBS console uses the native Windows Server Backup utility underneath. So you need another server but it does not have to be SBS 2011.
From a technet article Introducing the Small Business Server 2011 Backup Wizard:
SBS 2011, just like SBS 2008, includes a backup wizard that is integrated into the SBS console for the purpose of allowing administrators to quickly create a robust backup/restore strategy without requiring them to have prior experience in Windows backup technology. It’s a simple custom interface that calls upon the native Windows Server Backup utility to do its work while keeping much of the underlying complexity in the background.