A couple if days ago Microsoft released a new hotfix for Forefront Identity Manager 2010 R2.
Beside some fixes for CM and Client Add-ins this hotfix contains also the following new feature of the sync engine:
FIM Synchronization Service
This update includes ECMA 2.3. In this version, it is now possible to add custom schema pages that will be listed in the Synchronization Service Manager user interface. An example of how this feature is used can be seen in the Generic SQL connector.