how to add child to SOAPBodyElement

[Reuben Christie]

Hi i m newbie. and trying to learn SOAP. I wrote sample messege style
service.it gets deployed well but when i try to add a new SOAPBodyElement
inside the webservice method the following fault code is return back to
client. anybody can please help me learning this part.
<soapenv:Fault>
         <faultcode>soapenv:Server.userException</faultcode>

         <faultstring>java.lang.NullPointerException</faultstring>

         <detail>
            <ns1:hostname
xmlns:ns1="http://xml.apache.org/axis/";>ws20</ns1:hostname>
         </detail>
      </soapenv:Fault>


Here is my code for webservice method

public SOAPBodyElement[] listAssets(SOAPBodyElement[] bodies) throws
SOAPException {
                for (int i = 0; i < bodies.length; i++) {
                        SOAPBodyElement element = bodies[i];
                                        SOAPEnvelope 
envlp=element.getEnvelope();
                                        SOAPBody body=(SOAPBody) 
envlp.getBody();
                                        
body.addBodyElement(envlp.createName("childAsset"));

                }
                return bodies;
        }


I have tried other methods also using the signature

public Element[] listAssets(Element[] bodies) but that also doesnt work.
here is my wsdd file

<service name="assetservice" provider="java:MSG" style="message">
      <parameter name="className"
value="com.decisiontech.framework.demo.ListAssetService" />

      <parameter name="allowedMethods" value="listAssets" />
   </service>