Exchange webmail configuration

I am running Outlook Web Access and I need to enforce HTTPS. However, I cannot use forms-based authentication. I have to use HTTP authentication. When a user tries to access to the site via HTTP I need to redirect them to HTTPS and present the http authentication dialog. How can I accomplish this?

From serverfault Shawn

• Figured it out already. Create an asp page that redirects to https, and then set the IIS 403.4 error redirect to this file.

  From Shawn