django comments preview button not working

Question

I' using django 1.1.1 and its comment framework. But the "preview" button in the comment form always posts the comment directly without previewing it. I've edited both forms.html and preview.html.

forms.html

{% load comments i18n %}

<form class="form2 mt10 padding5" action="{% comment_form_target %}" method="post">
    <input type="hidden" name="next" value="{{request.path}}" />    
    ............
    ............        
  <p class="submit">
    <input type="submit" name="post" class="submit-post" value="{% trans "Post" %}" />
    <input type="submit" name="preview" class="submit-preview" value="{% trans "Preview" %}" />
  </p>

</form>

preview.html

{% extends 'base.html' %}
{% load comments i18n %}

{% block content %}
 <div id="content">   
<div id="commentFormWrapper">
    <h3 class="center mt5">Post a Comment</h3>
    <form class="form2 mt10 padding5" action="{% comment_form_target %}" method="POST">

     {% if next %}<input type="hidden" name="next" value="{{ next }}" />{% endif %}
    ...................
    ..................
    <p class="submit">
      <input type="submit" name="submit" class="submit-post" value="Post">
      <input type="submit" name="preview" class="submit-preview" value="Preview">
    </p>
  </form>
  </div>
  </div>
{% endblock %}

and, in my object page( where comment form will be displayed) I used:

   <div id="commentFormWrapper">
        <h3 class="head-bg center mt5">Post a Comment</h3>
        {% render_comment_form for idea %}
    </div>