PHP SoapClient无法使用代理访问webservice

Using SoapClient in PHP, I've come across a problem I have not been able to find a solution to.

I'm using a local copy of the wsdl file and I am using this setup:

$this->client = new \SoapClient(__DIR__ . '/../../some.wsdl',
                        array(
                                'proxy_host'    => $ip,
                                'proxy_port'    => $port,
                                'trace' => 1,
                                'exceptions' => true,
                                'cache_wsdl' => WSDL_CACHE_NONE
                        )
                    );

This gives error : "Forbidden" when calling :

$this->client->__call($method, $params)

I have tried calling __getFunctions()

$this->client->__getFunctions() 

that gives the list of all function in my WSDL file.

Am I missing something?

Debug code with like this :

<?php 
    try{
            $client = new SoapClient($wsdl, $params);
            $out = $client;
        }catch(Exception $e){
            $out =  array('error' => $e,  'libxml' => libxml_get_last_error());
        }catch(SoapFault $s){
            $out = array('error' => $s, 'libxml' => libxml_get_last_error());
        }
    var_dump($out);
    exit();