PHP: SOAP: Handle requests with class functions

To use a PHP class to handle the requests fetched by the server script you can simply assign the class file to the server:

$vClassName = 'MyHandlerClassName';
$vServer = new SoapServer('customer-ws_Customers.wsdl');
$vServer->setClass($vClassName);
$vServer->handle();

More information about SOAP Webservices: 
PHP : SOAP: Creating and Consuming a WSDL Web-Service