I believe the the given example is old and corresponds to JBPM4 .
For JBPM5 there are work item handlers for Human Task and would be a nice point to start
Eg : Human task Handler using MINA interfaces
Do you mean that I can extend HT functionality extending the WSHumanTaskHandler class??
Well this is a possible point of extension, but depends on your requirement . Check the executeWorkItem method, it basically implements the execution of this workitem.
I need to add some parameters to Human Task e.g. color, place!