CMaskedTextField, ActiveRecord::afterFind(), ActiveRecord::beforeSave()

afterFind.php

<?php

$this->widget('CMaskedTextField', array(
  'model' => $model,
  'attribute' => 'birthday',
  'mask' => '99.99.9999',
  'htmlOptions' => array('size' => 32)
));

public function beforeSave()
{
  if (!empty($this->birthday)) {
    list($day, $month, $year) = explode('.', $this->birthday);
    $this->birthday = implode('-', array($year, $month, $day));
  } else {
    $this->birthday = '0000-00-00';
  }
 
  return parent::beforeSave();
}

public function afterFind()
{
  list($year, $month, $day) = explode('-', $this->birthday);
  $this->birthday = implode('.', array($day, $month, $year));
  parent::afterFind();
}