With @Action and Reply Address - i am assuming that it is WS-Addressing parameters. Not sure how you got the MessageContext to be null. I had once was in a similar situation earlier (but was not able to access the MessageContext from the Endpoint method).
I followed the steps mentioned in this website http://www.ogrigas.eu/spring/2009/11/access-spring-ws-messagecontext-from-anywhere
Once MessageContext is retrieved (hopefully not null), the said parameters can be easily accessed by something like this
SoapMessage sm = (SoapMessage) mc.getRequest();
Iterator<SoapHeaderElement> iter = sm.getEnvelope().getHeader().examineAllHeaderElements();
while (iter.hasNext()) {
SoapHeaderElement she = iter.next();
log.info("\n"+she.getName().getLocalPart()+ " - "+she.getText());
}