PHP 创建webservice 在客户端调用的问题

soapserver.php
<?php
ini_set("soap.wsdl_cache_enabled", "0"); 
class service
{
    public function HelloWorld() {
      return  "Hello";
    }
    public  function Add($a,$b) {
      return $a+$b;
    }
}
$server=new SoapServer('TestSoap.wsdl',array('soap_version' => SOAP_1_2));
$server->setClass("service");
$server->handle();
?>serviceclient.php<?php
try {
$client=new SoapClient("http://localhost/soapService/TestSoap.wsdl");
echo $client->HelloWorld();
echo("<br />");
print_r($client->Add(1,2));
}
    catch ( SoapFault $e ) { echo $e->getMessage (); }
    catch ( Exception $e ) { echo $e->getMessage (); }
?>
TestSoap.wsdl<?xml version="1.0" encoding="UTF-8"?>
<wsdl:definitions xmlns:soap="http://schemas.xmlsoap.org/wsdl/soap/" xmlns:tns="http://localhost/soapService/" xmlns:wsdl="http://schemas.xmlsoap.org/wsdl/" xmlns:xsd="http://www.w3.org/2001/XMLSchema" name="TestSoap" targetNamespace="http://localhost/soapService/">
  <wsdl:types>
    <xsd:schema targetNamespace="http://localhost/soapService/">
      <xsd:element name="Add">
        <xsd:complexType>
          <xsd:sequence>
            <xsd:element name="in" type="xsd:string"/>
          </xsd:sequence>
        </xsd:complexType>
      </xsd:element>
      <xsd:element name="AddResponse">
        <xsd:complexType>
          <xsd:sequence>
            <xsd:element name="out" type="xsd:string"/>
          </xsd:sequence>
        </xsd:complexType>
      </xsd:element>
  <xsd:element name="HelloWorldResponse">
       <xsd:complexType>
       <xsd:sequence>
 
       <xsd:element name="out" type="xsd:string"></xsd:element>
       </xsd:sequence>
       </xsd:complexType>
      </xsd:element>
    </xsd:schema>
  </wsdl:types>
  <wsdl:message name="AddRequest">
    <wsdl:part name="a" type="xsd:int"/>
    <wsdl:part name="b" type="xsd:int"></wsdl:part>
  </wsdl:message>
  <wsdl:message name="AddResponse">
    <wsdl:part name="AddReturn" type="xsd:int"/>
  </wsdl:message>
  <wsdl:message name="HelloWorldRequest">  </wsdl:message>
  <wsdl:message name="HelloWorldResponse">
   <wsdl:part name="HelloWorldReturn" type="xsd:string"></wsdl:part>
  </wsdl:message>
  <wsdl:portType name="TestSoap">
    <wsdl:operation name="Add">
      <wsdl:input message="tns:AddRequest"/>
      <wsdl:output message="tns:AddResponse"/>
    </wsdl:operation>
    <wsdl:operation name="HelloWorld">
     <wsdl:input message="tns:HelloWorldRequest"></wsdl:input>
     <wsdl:output message="tns:HelloWorldResponse"></wsdl:output>
    </wsdl:operation>
  </wsdl:portType>
  <wsdl:binding name="TestSoapSOAP" type="tns:TestSoap">
    <soap:binding style="document" transport="http://schemas.xmlsoap.org/soap/http"/>
    <wsdl:operation name="Add">
      <soap:operation soapAction="http://localhost/soapService/Add"/>
      <wsdl:input>
        <soap:body use="literal"/>
      </wsdl:input>
      <wsdl:output>
        <soap:body use="literal"/>
      </wsdl:output>
    </wsdl:operation> <wsdl:operation name="HelloWorld">
   <soap:operation soapAction="http://localhost/soapService/HelloWorld" />
   <wsdl:input>
   <soap:body use="literal" />
   </wsdl:input>
   <wsdl:output>
   <soap:body use="literal" />
   </wsdl:output>
   </wsdl:operation>  </wsdl:binding>  <wsdl:service name="TestSoap">
    <wsdl:port binding="tns:TestSoapSOAP" name="TestSoapSOAP">
      <soap:address location="http://localhost/soapService/soapserver.php"/>
    </wsdl:port>
  </wsdl:service>
</wsdl:definitions>在IE浏览器输入: http://localhost/soapService/serviceclient.php 显示以下Hello
Procedure 'a' not present第一个方法能正确输出字符。第二个方法就报错。Procedure 'a' not present请各位老师指教。