Illegal extension attribute 'soapAction'

I got it up!! Finally, I got my first dummy WSDL, first created with notepad, load into SoapUI. Since there is no tool could allow me to do it in easy way, I have to verify the syntax with my own eyes.

On my first try, I got this stupid error when I first load into SoapUI. The cause of the error happened in wsdl:operation and soapAction is an illegal attribute? Ehrrr~ What is that means?

WSDLException (at /wsdl:definitions/wsdl:binding/wsdl:operation): faultCode=INVALID_WSDL: Encountered illegal extension attribute 'soapAction'. Extension attributes must be in a namespace other than WSDL's.    

I take a closer look into my first baby, then only I notice that I have mistakenly mess up the wsdl:operation with soapAction. This is something bad without a good tool to gauge my work.

<wsdl:binding name="HelloWorldSOAP12" type="tns:HelloWorldPort">
  <soap12:binding transport="http://schemas.xmlsoap.org/soap/http"/>
  <wsdl:operation name="HelloWorld" soapAction="http://helloWorld.huahsin68.org/helloWorld"/>
  <wsdl:input>
    <soap12:body use="literal"/>
  <wsdl:output>
    <soap12:body use="literal"/>
  </wsdl:output>
</wsdl:binding>

The fix is as follows:

<wsdl:binding name="HelloWorldSOAP12" type="tns:HelloWorldPort">
  <soap12:binding style="document" transport="http://schemas.xmlsoap.org/soap/http"/>
  <wsdl:operation name="HelloWorld">
    <soap12:operation soapAction="HelloWorldAction"/>
    <wsdl:input>
      <soap12:body use="literal"/>
    </wsdl:input>
    <wsdl:output>
      <soap12:body use="literal"/>
    </wsdl:output>
  </wsdl:operation>
</wsdl:binding>