Why is different the response of a WS with SoapUI that with Windows Foundation Classes Test Client?

Generally the response you get back from a webservice will be based on:

• the URI you are requesting
• the headers on your request (for example, Accept header, which specifies what format you want the response in)
• the content you are sending in your request (if any)

In SoapUI, you can look at the Raw tab to the left of your request to see all of this in one place. For example:

POST http://localhost:8080/ HTTP/1.1
Accept-Encoding: gzip,deflate
Content-Type: text/xml;charset=UTF-8
SOAPAction: "http://www.soapui.org/sample/buy"
Content-Length: 364
Host: localhost:8080
Connection: Keep-Alive
User-Agent: Apache-HttpClient/4.1.1 (java 1.5)

<soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/" xmlns:sam="http://www.soapui.org/sample/">
   <soapenv:Header/>
   <soapenv:Body>
      <sam:buy>
         <sessionid>?</sessionid>
         <buystring>?</buystring>
      </sam:buy>
   </soapenv:Body>
</soapenv:Envelope>

See if you can find a similar view in the other program, in order to compare the requests generated from each.