title: SoapClient Returns "NULL", but __getLastResponse() returns XML
body: <p>The variable $response in the below code is NULL even though it should be the value of the SOAP request. (a list of tides). When I call $client->__getLastResponse() I get the correct output from the SOAP service.</p>
  
  <p>Anybody know what is wrong here? Thanks! :)</p>
  
  <p>Here is my code : </p>
  
  <pre><code>$options = array(
    "trace" =&gt; true,
    "encoding" =&gt; "utf-8"
  );
  $client = new SoapClient("http://opendap.co-ops.nos.noaa.gov/axis/webservices/highlowtidepred/wsdl/HighLowTidePred.wsdl", $options);
  
  $params = array(
      "stationId" =&gt; 8454000,
      "beginDate" =&gt; "20060921 00:00",
      "endDate" =&gt; "20060922 23:59",
      "datum" =&gt; "MLLW",
      "unit" =&gt; 0,
      "timeZone" =&gt; 0
  );
  
  try {
   $result = $client-&gt;getHLPredAndMetadata($params);
   echo $client-&gt;__getLastResponse();
  }
  catch (Exception $e) {
    $error_xml =  $client-&gt;__getLastRequest();
    echo $error_xml;
    echo "\n\n".$e-&gt;getMessage();
  }
  var_dump($result);
  </code></pre>