title: Save data from Custom field in Shipping Method in Onepage Checkout
body: <p><strong>Hello</strong>,</p>
  
  <p><strong>My problem</strong>: I want to add a checkbox next to a shipping method and on checkout success, retrieve the value of the checkbox (checked/unchecked) and if it's checked, add a new record in a custom SQL table, where one of the value is the id of the order just created.</p>
  
  <p>I added the checkbox in <code>template/checkout/onepage/shipping_method/available.phtml</code> (that was the easy part). And the custom SQL table is already created.
  But now, how can I get the result of the checkbox and the orderid ?</p>
  
  <p>In <code>app/code/core/Mage/Checkout/controllers/OnepageController.php</code>, there is the save informations actions, can this be helpful ? I was thinking maybe if I overwrite the <code>saveOrderAction</code> I can achieve what I want, but I have no idea how.</p>
  
  <p>Thanks for your time, I hope someone can help me with this.</p>