Customizing Login Page

Hi,
I am not happy with the Netsuite branded login pages (Netsuite logo, url, and subsequent error pages - e.g. retry, session timeout, etc). I want customers to login from our website using everything branded to us. Once logged in I don't care as much but before logging in it needs to be our look and feel.

I was told I could simply do an HTTP POST using a script such as PHP and design my own form and error handling. I wrote the script (PHP) using CuRL and OpenSSL and can successfully post the username and password information however the returned headers show that the login redirects and returns the session timeout/retry login page (which will continue to loop if I re-submit). My only belief is that NetSuite expects the login page to come from their domain/IP thus returns the session timeout error. My code is good as I have used it for other secure (SSL-HTTPS)