Make CUrlManager::$_rules public/protected

I have a use case where because of I18N i need to dynamically add over 50 url rules at the begining of the request.

I use Yii::app()->urlManager->addRules($rules,false) to push them at the beginning of the rules chain.

Now, i want to cache these rules because it has no use to process these each time.

How should i do this if CUrlManager::$_rules is private ?