I'm afraid it's not possible using the out of the box components. However... it would be easy enough to implement custom ESB action that sets the ESB Message into the Smooks BeanContext before message filtering starts and then have something like a Groovy scriptlet to make the relevant updates to the ESB message. You couldn't make these updates using the normal Smooks configurations because Smooks does not manage the lifecycle of the ESB Message (it didn't create the ESB Message object).