protected SOAPMessage modifySOAPMessage(SOAPMessage soapMessage) throws SOAPException {
    // Intentionally blank
    return soapMessage;
  }
Override this in order to modify the SOAP message object before it's finally encoded. <br>
This might be useful to add SOAP Headers, which are not supported by this SOAPEncoder directly.
<br>
This is an example of how to add a security header: <code>
  protected SOAPMessage modifySOAPMessage(SOAPMessage soapMessage) throws SOAPException {
    SOAPFactory soapFactory = SOAPFactory.newInstance();
    String uri = "http://schemas.xmlsoap.org/ws/2002/12/secext";
    String prefix = "wss";
    SOAPElement security = soapFactory.createElement("Security", prefix, uri);
    SOAPElement usernameToken = soapFactory.createElement("UsernameToken", prefix, uri);
    usernameToken.addChildElement("Username", prefix, uri).setValue("test");
    usernameToken.addChildElement("Password", prefix, uri).setValue("test");
    security.addChildElement(usernameToken);
    soapMessage.getSOAPHeader().addChildElement(security);
    return soapMessage;
  }
</code>
soap/src/main/java/feign/soap/SOAPEncoder.java