Php soap客户端+得到空响应

I am trying to call a wcf ws from php client

WSDL https://ws-web.test.nhn.no/v1/AR?wsdl

$url = 'https://ws-web.test.nhn.no/v1/AR?wsdl';
$params = array('login' => '*****',
    'password' => '######',
    'soap_version' => SOAP_1_2,
    'trace' => TRUE);

$client = new SoapClient($url, $params);
var_dump($client->__soapCall("Ping")); 

With the above code I am always getting a null response and I am not able to call other functions from wsdl

If I try this with another syntax sometimes I get an action mismatch error and I am also getting a null response in Soap UI.

Based on the WSDL, the Ping function has an input message.

<wsdl:operation name="Ping">
    <wsdl:input wsam:Action="http://register.nhn.no/CommunicationParty/ICommunicationPartyService/Ping" message="tns:ICommunicationPartyService_Ping_InputMessage"/>
    <wsdl:output wsam:Action="http://register.nhn.no/CommunicationParty/ICommunicationPartyService/PingResponse" message="tns:ICommunicationPartyService_Ping_OutputMessage"/>
</wsdl:operation>

Input message consists of parameters defined here ...

<wsdl:message name="ICommunicationPartyService_Ping_InputMessage">
    <wsdl:part name="parameters" element="tns:Ping"/>
</wsdl:message>

And finally the Ping object doesn't look like it has any properties. Weird.

<xs:element name="Ping">
    <xs:complexType>
        <xs:sequence/>
    </xs:complexType>
</xs:element>

So give this a try.

$pingObj = new stdClass();
$client->__soapCall("Ping", [$pingObj]);