Hi, I have a customer portal set up which allows users to log in and view cases, etc.

If a user was to navigate directly to the cases vf page, they immediately get the Salesforce default Authorization Required page that says:  "You must first log in or register before accessing this page.
If you have forgotten your password, click Forgot Password to reset it. "

I know this page is usually displayed when there is an error, but there is no error.  I would like the page to redirect to the login page if the user is not logged in.  So lets say I have 2 pages:

1.  Login page

2.  Cases page

The default web address brings you to the Login page.  Once you log in, it takes you to the Cases page.  This all currently works fine.

But if a user goes straight to the cases page, it SHOULD automatically redirect them to the login page. But instead it brings them to the Authorization Required page. 

I dont see any way to do this.....???  How do I override this Authorization Required page?

Thanks