xpath问题

 

<?xml version="1.0" encoding="zh_cn"?>
<soap:Envelope
xmlnsoap=http://schemas.xmlsoap.org/soap/envelope/
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:xsd="http://www.w3.org/2001/XMLSchema">
<soap:Body>
<CheckUserNameResponse  xmlns="Oracle.Operator">              
             <CheckUserNameResult>

                 000653040

             </CheckUserNameResult>

        </CheckUserNameResponse>

    </soap:Body>

</soap:Envelope>


如何正确获取到CheckUserNameResult呢?
用//Envelope/CheckUserNameResponse/CheckUserNameResult不行