Changing standard translation of core messages

What would be the "correct" way to change the standard translation of core messages? Currently the file yii/framework/messages/[country]/yii.php is used for translating. I do not really want to change that file (or should I?), so how should I setup yii that instead this file is used: protected/messages/[country]/yii.php ?

Or even better, is it possible to make yii look into the latter directory first?

Please check: http://www.yiiframew…oc/cookbook/18/

That's it, thank you!

The link provided is wrong. The actual link is: