I'm facing this problem in jBPM6!
I added a jar containing my workItems implementations (in a custom package), then I added this jar in jbpm-console.war/WEB-INF/lib folder and regestered my handlers (classes implementing WorkItemHandler) into CustomWorkItemHandlers.conf.
My error is:
task '' has no work name.
May be little late..but, have you figured out the way of achieving the same you are trying here.
I If you have completed this task please share the steps in detail on how to achieve this.