Passing a hidden variable in the cart?

I’m trying to add a hidden form input to the checkout.tpl, but don’t see the value in checkout.php. Any thoughts?

In checkout.tpl:


Value of Foo = '{$foo_out}'


And in checkout.php:

```php sess_register('foo_in');
$smarty->assign('foo_out', $foo_in); ```

When pressing the Update button (no AJAX) on the View Cart page, I would expect [B]Value of Foo = 'bar'[/B] to print out but only get [B]Value of Foo = ''[/B]. Any thoughts?