I know that once a user has Windows credentials, the only way to logout would be to lose those windows credentials.  I have a configuration which removes the windows credentials, but I am using a different login mechanism than DNN.  What I need to be able to do is have the Logout button log the user out of DNN (i.e. remove the DNN cookie) and then redirect to a separate logoff page (i.e. not the login page).  What's the recommended approach for this?  I saw the following code:
        Private Sub Redirect()
            ' Redirect browser back to portal
            Response.Redirect(AuthenticationController.GetLogoffRedirectURL(PortalSettings, Request), True)
        End Sub
And I believe that if I just made the result of that GetLogoffRedirectURL be my particular url, that all would be well.  But I couldn't determine where that AuthenticationController logic lives in the DNN source.