As we have a redirection from the CAS server after authentication, the webflow is ended and the web session is destroyed and the confirmation screen won't work without deisabling the ```TerminateWebSessionListener```.
So that's why I'd like to keep the url finishing by */callbackAuthorize*, the new ```OAuthCallbackAuthorizeService``` (better name requested) and a different behaviour in the webflow for this kind of service : ```view-state``` instead of ```end-state```...