soap request属性具有空值

Question

我有一个肥皂请求，当我调用肥皂请求时，我的属性始终为null。以下是我的肥皂请求

<SOAP-ENV:Envelope xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/" xmlns:ns1="http://com.mysite/tf">
<SOAP-ENV:Body>
<ns1:Transfer>

<mmHeaderInfo>
<operatorCode>001</operatorCode>
<requestId>1</requestId>

</mmHeaderInfo>
<externalRefNo>p009</externalRefNo>
<accountNo></accountNo>
<accountAlias>MJMJMJM</accountAlias>
<accountName></accountName>
<transferDescription></transferDescription>
<amount>100</amount>
</ns1:Transfer>
</SOAP-ENV:Body>
</SOAP-ENV:Envelope>

下面是带有参数的webservice方法

 public class HeaderRequest{

       public string operatorCode{get;set;}
       public int requestId {get;set;}
       }

       [WebMethod]

        public ResponseParameters Transfer(HeaderRequest mmHeaderInfo, string externalRefNo, 
        string accountNo, string accountAlias, string accountName, string transferDescription, 
        string amount)
        {
 //All the above parameters are null
            ////does something and returns
        }

我的网络服务设置

    [WebService(Name = "MYService", Namespace = "http://com.mysite/tf")]

但是我所有的参数都为空。