Affiliate tracking code and Coupons

Hi,

I'll try and explain my issue as clearly as I can.

We use TradeTracker for our affiliate program but have hit an issue when it comes to offering Coupons and getting the tracking pixel/code to send back the final value with the discount applied.

For example,

- We offer the affiliate 10% commission for a sale.
- Customers click the Coupon offer (say 50% off) on their website and it tracks the checkout process all the way through to the Success.php page.

What should happen is the affiliate gets paid on the total paid AFTER the discount has been applied BUT Opencart isn't designed to return this method, it can only return getSubtotal or getTotal (relevent to this instance). As shown here: http://wiki.opencarthelp.com/doku.php?i ... rence#cart

As a result the customer is checking out with a £100 item, applying the 50% coupon discount and paying £50. But because there is no method for the coupon at this stage of the checkout the affiliate is getting a track-back of 10% of the original item price (£100) i.e, £10 rather than 10% of the discounted price (£50), therefore £5.

If this makes sense to those much smarter than I, please can you explain to me if this can be changed so that it can work??

Many thanks in advance.