CAS Client Plugin Doesn't Respect error.gsp

Hi,

Right now I am using the cas client plugin, but when a ticket is expired I get a stacktrace printed to the client.  All my other pages redirect to error.gsp.  Is there a way to make the plugin do the same?  I tried mapping "edu.yale.its.tp.cas.client.CASAuthenticationException" in my web.xml, but have had little luck:

        <error-page>
                <exception-type>edu.yale.its.tp.cas.client.CASAuthenticationException</exception-type>
                <location>/WEB-INF/grails-app/views/error.gsp</location>
        </error-page>

The above returns a blank screen, which isn't what error.gsp contains.

Thanks