Pass form variable from Checkout page to Confirm Order page?

Hi,

I'm new to customizing OpenCart. I've customized some aspects of 1.5.6.1, and I'm trying to do something which should be very simple but I'm having a very hard time.

What I've done is add a form variable 'newsletter' to the /checkout page (I'm actually using QuickCheckout, so the page is at: route=quickcheckout/checkout ). That variable is ID/name='newsletter'. It is a checkbox, ticked by default, with a value of '1'.

What I want to do is when I click the [Continue] button on the bottom of the page (when the user is not logged in, as they will be a guest at this point), when I get to the next page, which is the page with the [Confirm] button on it, when they click that [Confirm] button on the next page (which is in the function /catalog/model/checkout/order.php at the bottom of the function) I want to be able to see if the user left that form variable ('newsletter') checked, or on, or if the user unchecked it. So, I would have a value of '1' if they left it checked, and no value (or unset) if they did not check it.

Can someone please tell me how to go about this? I've looked at template files, and just about everywhere, trying to see how to do this, but it escapes me at the moment?

TIA,
-Brett