I solved it myself.
Just for the protocol (and others having the same problem), you can receive the original URL from the session attribute map where the full request is saved:
Code:
private String obtainFullRequestUrl(HttpServletRequest request) {
HttpSession tmpSession;
SavedRequest tmpSavedRequest;
String tmpUrl = null;
tmpSession = request.getSession();
tmpSavedRequest = (SavedRequest) tmpSession.getAttribute(AbstractProcessingFilter.ACEGI_SAVED_REQUEST_KEY);
if (null != tmpSavedRequest) {
tmpUrl = tmpSavedRequest.getRequestURL();
}
return tmpUrl;
}