Can you localise validation error messages in plugins? (CakePHP/2.5)

I’m writting a plugin and I can successfully localise all strings:

<?php echo __d('foo_manager', 'button_insert_new_foo'; ?>

… except validation errors:

class TeddyBear extends FooManagerAppModel{
    public $validate = array(
        'date' => array(
            'arbitraryNameOne' => array(
                'required' => 'create',
                'rule' => 'notEmpty',
            'arbitraryNameTwo' => array(
                'rule' => 'date',
                'message' => 'error_date_not_valid', // Ignored and displayed as is even when translation exists

Validation errors are not even mentioned at Internationalizing CakePHP Plugins. Is it just not supported?