Callback in PHP client

See more:

ASP.NET

WCF

PHP

SOAP

webservice

I have created a WCF Service with callback and using wsDualHttp Binding. I want to connect to this service using PHP client. In PHP , SoapClient is used to call the WCF service like below:

$wsdl = "http://pathto/file.svc?wsdl"
$client = new SoapClient($wsdl, array('trace' => $trace, 'exceptions' => $exceptions));
$response = $client->somefunction();

Please guide in getting for callback in PHP.