title: Magento Save Order function where it is?
body: <p>I'm checking since hours into magento files.
  Now I'm in checkout onepage <code>/checkout/onepage/reviews/info.phtml</code>, the order is saved with this call to Ajax, </p>
  
  <pre><code>&lt;script type="text/javascript"&gt;
  //&lt;![CDATA[
      review = new Review('&lt;?php echo $this-&gt;getUrl('checkout/onepage/saveOrder', array('form_key' =&gt; Mage::getSingleton('core/session')-&gt;getFormKey())) ?&gt;', '&lt;?php echo $this-&gt;getUrl('checkout/onepage/success') ?&gt;', $('checkout-agreements'));
  //]]&gt;
  &lt;/script&gt;
  </code></pre>
  
  <p>I'm new to this syntax, there is no saveOrder file in onepage template folder, I need to hack the saveOrder action to change the redirect from succes page to a payment gateway and come back. 
  Where this method is? I really don't understand this call to ajax like a new object instance.</p>
  
  <p>Any help will be appreciated.</p>