Client Rpc call on detach

[code]
widget.addAttachHandler(new Handler() {

        @Override
        public void onAttachOrDetach(AttachEvent event) {
            if (!event.isAttached()) {
                rpc.onClientDetach();
            }
        }
    });

[/code]Rpc don’t call because the connector was detached. How can I do this?