Thanks again, Steve! I figured it out myself! All I had to do is use the old cart.php, as you suggested and the take this part here from the older "checkout.php":
<td class="main" width="50%" align="right"><table cellpadding="2" cellspacing="0" border="0">
<tr>
<td class="main"><b>Update Cart:</b></td>
</tr>
<tr>
<td><?php echo tep_image_submit('button_update_cart.gif', IMAGE_UPDATE_CART, 'name="updateQuantities" id="updateCartButton"');?></td>
</tr>
</table></td>
and paste it into the new one, right after:
if (MODULE_ORDER_TOTAL_DISCOUNT_COUPON_STATUS == 'true'){
echo '<table cellpadding="2" cellspacing="0" border="0">
<tr>
<td class="main"><b>Have A Coupon?</b></td>
</tr>
<tr>
<td class="main">' . tep_draw_input_field('coupon', '') . '</td>
<td class="main">' . tep_image_submit('button_redeem.gif', IMAGE_REDEEM_VOUCHER, 'id="voucherRedeemCoupon"') . '</td>
</tr>
</table>';
}
//EOF KGT
?></td>
<td class="main" width="50%" align="right"><table cellpadding="2" cellspacing="0" border="0">
</table></td>
So, that is fixed, thanks again! :-)
The new question I had, about the "must accept terms and conditions" still gives me a headache though. Is there no way around the MATC module and manually integrating it into this mod? It doesn't have to be too fancy...