title: C# Selenium WebDriver FireFox Profile - using proxy with Authentication
body: <p>When you set proxy server parameter in the code below if your proxy server requires authentication then FireFox will bring Authentication dialog and basically you can't fill it in automatically. 
  So is there is anyway to set <strong>USERNAME</strong> and <strong>PASSWORD</strong> ?</p>
  
  <pre><code>FirefoxProfile profile = new FirefoxProfile();
  String PROXY = "192.168.1.100:8080";
  OpenQA.Selenium.Proxy proxy = new OpenQA.Selenium.Proxy();
  proxy.HttpProxy=PROXY;
  proxy.FtpProxy=PROXY;
  proxy.SslProxy=PROXY;
  profile.SetProxyPreferences(proxy);
  FirefoxDriver driver = new FirefoxDriver(profile);
  </code></pre>
  
  <p>If you try to format proxy string to something like that <code>http://username:pass@192.168.1.1:8080</code>
  You get error that string is invalid. So I wonder there is must be a way of achieving this.</p>
  
  <p>Any help would be appreciated.</p>