Host rewrite with SSL offloading

Hello, Am trying to accomplish the following task, that looks very easy, but currently cannot figure out/find out on devcentral or kb. I would like to use my BIG-IP with LTM as a reverse proxy replacement with SSL offloading towards internet, i.e.: External application: https://app.external.com Internal application: http://app.internal.com Everything appended after the URL should be kept as it is (no URI rewrite), means: https://app.external.com/a ----->http://app.internal.com/a https://app.external.com/b ----->http://app.internal.com/b so basically, I only want the host name rewritten, as we are using IIS host headers to bind on a single IP multiple websites. In order to accomplish that, I have setup a VS with client SSL profile, and applied ProxyPass iRule. Nevertheless, I can see that when the server response is on http, the client get the http URL, than the HTTPS back and this trows a client error. ProxyPass log is: Rule /Common/ProxyPass : VS=/Common/test_vs_https_app.external.com, Host=app.external.com, URI=/a/: Changing response header Location: http://app.internal.com/a/login.do with http://app.external.com/a/login.do As you can see, the response back to client is in http, rather than https, and this obviously generates an error. Can you please help me in obtaining such objective?