Using ReCaptcha as form element

Questions Components & MVC
1

Hello,

I found ReCaptcha component in ZF documentation. Is it possible to use it in form class? I tried something like this but with no luck.

$captcha = new ReCaptcha(array(
    'private_key' => '',
    'public_key' => '')
);

$this->add(array(
    'name' => 'captcha',
    'options' => array(
        'label' => 'Verification',
        'captcha' => $captcha,
    ),
    'type' => 'Zend\Form\Element\Captcha',
));