How to get Potential Owner from task summary - JBPM 6.5

I am developing a task inbox and from my frontend I am calling http://localhost:8080/jbpm-console/rest/query/task?potentialOwner=potOwner for getting task summary but this query does not retrieve the Potential Owner. I know we can add business data to subject/description using #{} into task properties from business process modeler but I do not know how to set there the potential owner. Do you know if it is possible?

Thanks in advanced!