Behavior translate et image

Bonsoir,

Je souhaite avoir une image différente pour mes articles traduits mais je ne parviens pas à sauvegarder mes images.

mon PostsController:

public function admin_add() {
        if ($this->request->is('post')) {
            $this->Post->create();
            if(!empty($this->request->data['Post']['image_file']['tmp_name']))
            {
                $dir = WWW_ROOT.'uploads'.DS.'articles';
                $r = move_uploaded_file($this->request->data['Post']['image_file']['tmp_name'], $dir.DS.$this->request->data['Post']['image_file']['name']);
                $this->request->data['Post']['image'] = $this->request->data['Post']['image_file']['name'];
                unset($this->request->data['Post']['image_file']);
            }
            if ($this->Post->saveAssociated($this->request->data)) {
                $this->Session->setFlash('The post has been saved.','flash_success');
                return $this->redirect(array('action' => 'index'));
            } else {
                $this->Session->setFlash(__('The post could not be saved. Please, try again.','flash_failure'));
            }
        }
        $categories = $this->Post->Category->find('list');
        $users = $this->Post->User->find('list');
        $this->set(compact('categories', 'users'));

    }

mon model:

public $actsAs = array(
        'Translate' => array(
            'name' => 'nameTranslation',
            'image' => 'imageTranslation',
            'content' => 'contentTranslation'
        )
    );

ma vue:

<?php echo $this->Form->create('Post'); ?>

    <?php foreach (Configure::read('Config.languages') as $lang): ?>
        <?php echo $this->Form->input('Post.name.'.$lang); ?>
    <?php endforeach; ?>
    <?php foreach (Configure::read('Config.languages') as $lang): ?>
        <?php echo $this->Form->input('Post.content.'.$lang); ?>
    <?php endforeach; ?>
    <?php foreach (Configure::read('Config.languages') as $lang): ?>
        <?php echo $this->Form->input('Post.image_file.'.$lang, array('type'=>'file')); ?>
    <?php endforeach; ?>

une idée sur l'erreur que j'ai faite?