OPENERP code

return {
            'name': _('Attachments'),
            'domain': domain,
            'res_model': 'ir.attachment',
            'type': 'ir.actions.act_window',
            'view_id': False,
            'view_mode': 'tree,form',
            'view_type': 'form',
            'limit': 80,
            'context': "{'default_res_model': '%s','default_res_id': %d}" % (self._name, res_id)
        }


var action = {
                    type: 'ir.actions.act_window',
                    res_model: 'mail.compose.message',
                    view_mode: 'form',
                    view_type: 'form',
                    views: [[false, 'form']],
                    target: 'new',
                    context: context,
                };

                self.do_action(action);
                self.on_cancel();