title: Magento doesn't save value on 'save'
body: <p>I have a custom module that adds a field to an element in </p>
  
  <pre><code>&lt;?php
  
  class NS_MN_Block_Cms_Page_Edit_Tab_Main extends Mage_Adminhtml_Block_Cms_Page_Edit_Tab_Main
  {
  
  public function _prepareForm()
  {
  parent::_prepareForm();
  
   $fieldset = $this-&gt;getForm()-&gt;getElements()-&gt;searchById('base_fieldset');
  
  $fieldset-&gt;addField('bar', 'text',
      array(
          'label' =&gt; Mage::helper('cms')-&gt;__('BaR'),
          'class' =&gt; 'input-text',
          'name'  =&gt; 'bar',
          'required' =&gt; false
      )
  );
  return $this;
  }
  }
  </code></pre>
  
  <p>I have added the <code>bar</code> field into the <code>cms_page</code> table and the field is rendered, but when I save the cms page, the field is not saved to the database.</p>
  
  <p>Could anyone tell me what I am overlooking here?</p>