yii 1.1 datepicker's language into ajax rendered view

I am a newbie in Yii and I have a question. I have written an app with Yii (starting from Gii) where I have the admin view for a model with datepicker filters (thanks this tutorial: http://ift.tt/1HnFw66). My language in main config file is setted to "it".
It works fine, BUT if I modify my application for rendering this view after ajax request (first I open a page of my site with the layout, then click on an ajax link to request admin view (without layout)), datepicker's language is setted to japanese first time! How can I resolve this?
I have already included this code in my layout file:

Yii::app()->clientScript->registerScriptFile(Yii::app()->getClientScript()->getCoreScriptUrl() . '/jui/js/jquery-ui-i18n.min.js');