django-recaptcha validation problems

Hi,

I am using django-recaptcha and I want to use it inside the registration form. In the website [1], inside the Field section says: "A ReCaptcha widget will be rendered with the field validating itself without any further action required from you". Actually seems is not validating anything. Anyone had similar experience?

Thanks.
----------------------------- forms.py -----------------
from registration.forms import RegistrationFormUniqueEmail
from captcha.fields import ReCaptchaField

class RecaptchaRegistrationForm(RegistrationFormUniqueEmail):
    recaptcha = ReCaptchaField()
----------------------------- forms.py -----------------

----------------------------- urls.py -----------------
url(r'^accounts/register/$', register, { # Overwrite registration url
    'backend': 'registration.backends.default.DefaultBackend',
    'form_class': RecaptchaRegistrationForm,
    }, name='registration_register'),

url(r'^accounts/', include('registration.backends.default.urls')),
----------------------------- urls.py -----------------

----------------------------- registration_form.html -----------------
{% extends "base.html" %}
{% block title %}Register for an account{% endblock %}
{% block container %}

<table>
    <form method='post' action=''>{% csrf_token %}
        {{ form }}
        <tr><td></td><td><input type="submit" value="Send activation email" /></td>
    </form>
</table>
{% endblock %}
----------------------------- registration_form.html -----------------

----------------------------- rendered code -----------------

<form method='post' action=''><input type='hidden' name='csrfmiddlewaretoken' value='blablaq' />
    <tr><th><label for="id_username">Username:</label></th><td><input class="required" id="id_username" maxlength="30" name="username" type="text" /></td></tr>
    <tr><th><label for="id_email">E-mail:</label></th><td><input class="required" id="id_email" maxlength="75" name="email" type="text" /></td></tr>
    <tr><th><label for="id_password1">Password:</label></th><td><input class="required" id="id_password1" name="password1" type="password" /></td></tr>
    <tr><th><label for="id_password2">Password (again):</label></th><td><input class="required" id="id_password2" name="password2" type="password" /></td></tr>
    <tr><th><label for="id_recaptcha">Recaptcha:</label></th><td><script type="text/javascript">
    var DjangoRecaptchaOptions = {
  "lang": "en"
};
    if (typeof RecaptchaOptions !== 'object') {
        RecaptchaOptions = DjangoRecaptchaOptions;
    } else {
        for (key in DjangoRecaptchaOptions) {
            RecaptchaOptions[key] = DjangoRecaptchaOptions[key];
        }
    }
</script>
<script type="text/javascript" src="http://www.google.com/recaptcha/api/challenge?k=6blablaC&hl=en"></script>
<noscript>
  <iframe src="http://www.google.com/recaptcha/api/noscript?k=6blablaC&hl=en" height="300" width="500" frameborder="0"></iframe><br />
  <textarea name="recaptcha_challenge_field" rows="3" cols="40"></textarea>
  <input type='hidden' name='recaptcha_response_field' value='manual_challenge' />
</noscript>
</td></tr>
        <tr><td></td><td><input type="submit" value="Send activation email" /></td>
</form>
----------------------------- rendered code -----------------


The Exact version I am using are:
Django==1.5
django-recaptcha==0.0.6
django-registration==0.8
recaptcha-client==1.0.6


[1] - https://github.com/praekelt/django-recaptcha