如何在php数组中实现xml属性

Question

I'm trying to send XML to a call in a PHP array format using a SoapClient object and the __soapCall method within.

The problem I'm having is that the "identification" element has an attribute called "type". How do I implement the attribute and its value in the following PHP array?

I'm able to connect but I a fault in te response saying I'm not providing certain data. In SoapUI I get the same error response when leaving out the attribute and its value. So this has to be the problem.

$client = new SoapClient("webserviceblabla?wsdl");

    $method1 = "search";


        $xmlRequestArray = [
                      "auth" => [
                          "userName" => test,
                          "password" => "test"
                      ],
                      "maximumNumberOfHits" => t,
                      "searchOptions" => [
                        "identification" =>  5000000
                      ]
                    ];

    $response = $client->__soapCall($method1, array($xmlRequestArray));

             echo '<pre>'; 
             print_r($response); 
             echo '</pre>';