In order to assist with migrating Security & Distribution Groups to Windows Small Business Server 2008, Microsoft has provided the “Active Directory Group Converter”. This wizard will make legacy groups visible within the SBS 2008 Console. However, it will only convert groups that a stored within the “Security Groups” or “Distribution Groups” OU’s. So, if your groups are not already stored within one of those containers. you will have to move them there prior to running the wizard.
Groups not showing up within “SBS 2008 AD Group Converter”