Stealth Redirection or URL Hiding

the chrome and ie browsers still show news.xxx.com in the URL area

And they are going to. You're replacing the Host header as the request flows through the proxy. The client isn't going to see this. The server will though. The Host header is just that, an HTTP header. It's a value in the HTTP request, and has basically nothing to do with browser navigation. In fact in HTTP/1.0 the Host header isn't even required.