The Fast Lane checkout doesn't skip the cart. This is the page that displays when a customer adds an item to the cart using the Buy Together module. The reason the cart.php page is skipped is to get the customers through the checkout as fast as possible to reduce abandoned carts.
There are 2 options to change this:
Option 1. Add the coupon box to the "Added to your cart" page:
Near line 70, after this code:
Code:
<td>{include file="buttons/button.tpl" button_title=$lng.lbl_proceed_checkout style="button" href="`$catalogs.customer`/cart.php?mode=checkout"}</td>
</tr></table></div>
</td>
</tr>
Insert this:
Code:
{* Display Coupon on 'Added Page' *}
<tr>
<td colspan="3">
{include file="modules/Discount_Coupons/add_coupon.tpl}
</td></tr>
---
Option 2.
Change the link that goes directly to the checkout to go to the cart.php page instead.
It is in the skin1/modules/Buy_Together/buy_together_added.tpl.
Change this (two places):
Code:
{include file="buttons/button.tpl" button_title=$lng.lbl_proceed_checkout style="button" href="`$catalogs.customer`/cart.php?mode=checkout"}
to this:
Code:
{include file="buttons/button.tpl" button_title=$lng.lbl_proceed_checkout style="button" href="`$catalogs.customer`/cart.php"}
Then login to the languages section of the admin and change the language variable lbl_proceed_checkout to 'continue to cart'