According to the page http://blog.exadel.com/2009/08/25/seam-exception-handling/ using exception handling (via pages.xml or the @Redirect annotation) to do a redirect is not possible during the authentication process.
Another alternative I have tried is using the following to redirect, which also seems to be ignored.
final ExternalContext ctx = facesContext.getExternalContext( );
ctx.redirect( "/upsell.xhtml" );
How can I enforce a redirect during the authentication process to another view id?