Workaround for this problem - get variable at HT2 from task contetnt :
public Object getProcessParameter(Long taskId, String key){
TaskService taskService = getLocalTaskService();
Task task = taskService.getTask(taskId);
TaskData taskData = task.getTaskData();
Long documentContentId = taskData.getDocumentContentId();
Content content = taskService.getContent(documentContentId);
Map<?, ?> variableMap = ((Map<?, ?>) ContentMarshallerHelper.unmarshall(content.getContent(), null));
retObj = variableMap.get(key);
}
I don't know why it is not available as process variable.
Regards