Adding a new checkbox in Checkout Step 1 - the value doesn't pass onto the next page

[chillout_buddha]

I have added a checkbox for insurance in Checkout Step 1 (file: tpl_checkout_shipping_default.php):


<?php
$insurance = 0.05 * $_SESSION['cart'] -> show_total();
?>
<fieldset id="insurance"><legend>Insurance</legend>
<div class="important forward"><?php echo "$".$insurance; ?></div>
<?php echo zen_draw_checkbox_field("insurance", $insurance, '', 'id="insurance"'); ?>
<label for="insurance" class="checkboxLabel" >Tick to pay additional insurance</label>
</fieldset>


But when I go to the next page, the value does not seem to be carried there. I tried $_POST['insurance'] & $GLOBALS['insurance']. Seems like a very simple issue. Can someone help?

Thanks