This presentation shows how user tasks status, managed by Activiti inside Alfresco, can be synchronized with any other system. By using Activiti parser extension, customized listeners can be assigned for every workflow launched in Alfresco. Once each of the events associated to this listeners has been triggered, synchronization operations can be performed.
You can find a source code template, as an Alfresco AMP module, at https://github.com/keensoft/alfresco-user-task-listener. Feel free to provide an
ExternalTaskSystem implementation and let me know your comments.