modify orders update button template code, how??

[tlyczko]

I have this code in tpl_shopping_cart_default.php:

<td class="cartQuantityUpdate" width="10%">
<?php
if ($product['buttonUpdate'] == '') {
echo '' ;
} else {
echo $product['buttonUpdate'];
}
?>
<br /><br />
<?php echo '<a href="' . $product['buttonUpdate'] . '">' . zen_image_button(BUTTON_IMAGE_CHECKOUT, BUTTON_UPDATE_ALT2) . '</a>'; ?>

</td>

The first part is the normal usage of a button for updating the cart item's quantity.

The second part in bold is my effort to do this with a ZC-style CSS button.

The CSS button presently does not work -- it jumps back to the home page.

Obviously the link is not correct for updating the item quantity and total price for X number of units -- what should it be??

Thank you, Tom