Support non-WSDL mode

[clue]

$wsdl - URI of the WSDL file or NULL if working in non-WSDL mode.
$options - An array of options. If working in WSDL mode, this parameter is optional. If working in non-WSDL mode, the location and uri options must be set, where location is the URL of the SOAP server to send the request to, and uri is the target namespace of the SOAP service.

http://php.net/manual/en/soapclient.soapclient.php