如何在soap请求中传递一个参数和xml数据

Question

I have soap request in xml format. I want to convert into php SOAP. Request

    <s:Envelope xmlns:s="http://schemas.xmlsoap.org/soap/envelope/">
    <s:Body>
    <AddContact xmlns="http://thankqportal.com/eModulesAPI" 
     xmlns:i="http://www.w3.org/2001/XMLSchema-instance">
       <token>efgh5678</token>
       <contactXml>
         <Contact xmlns="http://thankqportal.com/eModulesAPI/Contact.xsd" 
                 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
                 xmlns:xsd="http://www.w3.org/2001/XMLSchema">
              <title>Mr</title>
              <firstname>Luke</firstname>
              <keyname>Hawkins</keyname>
        </Contact>
      </contactXml>
  </AddContact>
  </s:Body>
 </s:Envelope>

Please help me here. I am stuck with contact xml. It is inner xml of xml. So How can I pass the xml to soap api.

I have written the code as per below:

  $xml = "<Contact>
        <firstname>$fname</firstname>
        <keyname>$keyname</keyname>
        </Contact>"; 
$args = array("token" =>$token, "contactXml"  => new SoapVar($xml, XSD_ANYXML));

try {
        $result =   $soapClient->AddContact($args);

    } catch (SoapFault $e) {
       echo '<pre>';    
       echo "Error!:    ";
       echo $e -> getMessage ();
   }

But it gives the error: Error!: Object reference not set to an instance of an object.

So please help me here where I am wrong in my code.