Authentication: SSO fallback if mod_auth_kerb fails

Hi,

our intranet has SSO enabled with mod_auth_kerb and works fine.
But now we are planing to use some Thin clients without integrating
them into the kerberos domain. Of course the authenticaion fails
when accessing the drupal site, with a "401 Authorization Required"
error page.

I`ve tried to use a custom error page with a meta-refresh to redirect
to the drupal site. But unfortunately this redirects back to the sso
url.

Is there any way get this scenario to work (e.g. set a cookie within
the error page an redirect than, like a manual logout...)?

Thanks in advance!

Ralf