如何调试SOAP连接

Setting up my first SOAP connection. Code below. I can pull down AvailableContent method but cant seem to access any other objects. Is there anything immediately wrong with my code, or is there something I can ask the service provider.

$soapClient = new SoapClient('http://contentcafe2.btol.com/contentcafe/contentcafe.asmx?wsdl', array("trace" => 1, "exception" => 0));

$auth = array(
   'userID'   => 'XXXXXXX',
   'password' => 'XXXXXXX',
   'key'  => '9781608198214',
   'content' => 'AvailableContent'
);


try{

    $response = $soapClient->Single($auth);

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


}catch (Exception $e) {



}

I think you should use a SOAP client such as SoapUI - http://www.soapui.org/ - to test your soap handshake instead of writing a code to do same.