SM Incidents Web Service SOAP - Modify WSDL document

Hello, I am having troubles trying to filter the incidents created in SM.

 

In the wsdl document there is the RetrieveIncidentList function, in SoapUI we can see the structure of the XML:

<soapenv:Envelope xmlns:soapenv="">schemas.xmlsoap.org/.../" xmlns:ns="">schemas.hp.com/.../7">
   <soapenv:Header/>
   <soapenv:Body>
      <ns:RetrieveIncidentListRequest attachmentInfo="" attachmentData="" ignoreEmptyElements="true" updatecounter="" handle="" count="" start="" attachmentType="">
         <ns:keys query="" updatecounter="">
            <ns:IncidentID type="String" mandatory="" readonly=""></ns:IncidentID>
         </ns:keys>
      </ns:RetrieveIncidentListRequest>
   </soapenv:Body>
</soapenv:Envelope>

I want to see some specific incident, lets say, closed incidents, in order to do that I can put the Status label inside keys like this:

<soapenv:Envelope xmlns:soapenv="">schemas.xmlsoap.org/.../" xmlns:ns="">schemas.hp.com/.../7">
   <soapenv:Header/>
   <soapenv:Body>
      <ns:RetrieveIncidentListRequest attachmentInfo="" attachmentData="" ignoreEmptyElements="true" updatecounter="" handle="" count="" start="" attachmentType="">
         <ns:keys query="" updatecounter="">
            <ns:IncidentID type="String" mandatory="" readonly=""></ns:IncidentID>
            <ns:Status type="String" mandatory="" readonly="">Closed</ns:Status>
         </ns:keys>
      </ns:RetrieveIncidentListRequest>
   </soapenv:Body>
</soapenv:Envelope>

This works just fine in SoapUI. But when I try to do that in PHP it seems like retrieveIncidentList() function doesn't care about parameters that are not in the default XML Request.

 

I have the following code (PHP):

<!DOCTYPE html>
<html>
<head>
  <title></title>
</head>
<body>
  <?php
    $incidentID = "";
    $status = "Closed";

    $wsdl = "http://<server>:<port>/SM/7/IncidentManagement.wsdl";
    $credentials = array('login'    => "user",
		         'password' => "password");
    $soap = new SoapClient($wsdl, $credentials);
    $parameters = array("ignoreEmptyElements" => "true",
				     "keys" => array("IncidentID" => $incidentID,
					             "Status" => $status));
    $xml = $soap -> retrieveIncidentList($parameters);

I need to know how to tell to the web service to listen the other parameters and I think is modifying the WSDL document, but I don't know how and where to do that.