cakephp zawiera problem z warunkami stowarzyszenia

Mam następujące skojarzenia

post-> primary-> secondary

$results = $this->Post->find('all', array(
    'conditions' => array(
        'Post.post_id =' => 2,
        'Primary.secondary_id !=' => null
    ),
    'contain' => array(
        'Primary' => array(
            'Secondary' => array(
                'conditions' => array('Secondary.short_code =' => 'code')
            )
        )
    )
));

Zwraca to.

Array
(
    [0] => Array
        (
            [Post] => Array
                (
                    [id] => 2
                    [created] => 2012-10-29 09:48:29
                    [modified] => 2012-10-29 09:48:29
                )

            [Primary] => Array
                (
                    [id] => 3
                    [secondary_id] => 6
                    [Secondary] => Array
                        (
                            [id] => 6
                            [short_code] => code
                            [created] => 2012-10-31 11:19:56
                            [modified] => 2012-10-31 11:20:03
                        )

                )

        )

Jednak kiedy się zmieniam

'conditions' => array('Secondary.short_code =' => 'code')

do

'conditions' => array('Secondary.short_code !=' => 'code')

nadal zwraca pierwotny rekord, gdy tego nie chcę.

Array
(
    [0] => Array
        (
            [Post] => Array
                (
                    [id] => 2
                    [created] => 2012-10-29 09:48:29
                    [modified] => 2012-10-29 09:48:29
                )

            [Primary] => Array
                (
                    [id] => 3
                    [secondary_id] => 6
                    [Secondary] => Array
                        (
                        )

                )

        )

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