Datepicker In Cgridview Filter Format

Hi,

I have problem with DatePickers in CGridView filter. There are 3 columns with DatePicker filter. I want it bo be in Polish language and it is. I also need it to have format: yy-mm-dd. Unofortunately it has the format only for the initial request to the page. After ajax update of the CGridView (doesn't matter if I changed one of datepickers or any other filter) - when I try to change/set date in datepicker it changes the format to dd.mm.yyy. Why? I have javascript function that is being called after ajax update.
Here is the code (part of the CGridView plus the javascript function):

$this->widget('bootstrap.widgets.TbExtendedGridView', array(
	'id'=>'projects-grid',
	'type' => 'striped condensed',
	'dataProvider'=>$model->search(),
	'filter'=>$model,
	'afterAjaxUpdate' => 'reinstallDatePicker',
	'ajaxUrl' => $this->createUrl('projects/admin'),
	'columns'=>array(
		array(
			'name' => 'idProject',
			'htmlOptions' => array('width' => '60px', 
                        'style' => 'text-align: right;', 
                        'class' => 'gridIdColumn'),
		),
		'name',
		array(
			'name' => 'projStart',
			'filter' => $this->widget('zii.widgets.jui.CJuiDatePicker', 
				array(
					'model' => $model,
					'attribute' => 'projStart',
					'language' => 'pl',
					'htmlOptions' => array(
						'id' => 'Projects_projStart',
						'dateFormat' => 'yy-mm-dd',
					),
					'options' => array(  // (#3)
	          'showOn' => 'focus', 
	          'dateFormat' => 'yy-mm-dd',
	          'showOtherMonths' => true,
	          'selectOtherMonths' => false,
	          'changeMonth' => false,
	          'changeYear' => false,
          )
				),
				true),
		),
		array(
			'name' => 'confirmStart',
			'filter' => $this->widget('zii.widgets.jui.CJuiDatePicker', 
				array( ....

Yii::app()->clientScript->registerScript('re-install-date-picker', "
function reinstallDatePicker() {
  $('#Projects_projStart').datepicker($.datepicker.regional[ 'pl' ]);
  $('#Projects_projStart').datepicker({dateFormat: 'yy-mm-dd'});
  $('#Projects_confirmStart').datepicker($.datepicker.regional[ 'pl' ]);
  $('#Projects_presentationDate').datepicker($.datepicker.regional[ 'pl' ]);
}
");

I also use YiiBooster but I don't think it's relevant.