lets dump API's here ....

// if you want to put/get something in/from the pageFlowScope, use thisMap
pfsMap = AdfFacesContext.getCurrentInstance().getPageFlowScope();
pfsMap.put(key, value); // pfsMap.put("#{pageFlowScope.param}, "sample");
pfsMap.get(key); // pfsMap.get("#{pageFlowScope.param}

// if you want to set bean's property value, use this
MyBackingBean bean = (MyBackingBean)pfsMap.get("my_backing_bean_name"); // the name under which the bean is registered in the task flow
bean.setMyParam(newValue);