Task forms simply returns a "Failure" dialog box and are not displayed.
The form is in the bar file:
cygwin# unzip my_bpmn2_diagram.bar
warning: my_bpmn2_diagram.bar appears to use backslashes as path separators
warning: stripped absolute path spec from /askUser.form
warning: stripped absolute path spec from /my_bpmn2_diagram.activiti.bpmn20.xml
Comparing the example processes in ACT_GE_BYTEARRAY and the one I deployed, mine have the process and task form prefixed with "\" where as the examples do not.