Sharepoint / Exchange Task Synchronisation

Hi

I configured Task Synchronization between our Exchange 2013 and SharePoint Server 2013. The tasks from "MySite" are syncing successfully. But it happen only for my personal tasks listed in "MySite". Why are my aggregated tasks from other site collections not synchronized? Does it work only for personal tasks in "MySite" but not for aggregated tasks?

Thanks for your help

Urs