Coupon for Tracking Only -- problem: no discount = not tracked :(

I have a client who wants to use a coupon code to allow a percentage of the sale to be donated to various charities. She doesn't want a discount applied to the sale, just to be able to track the code used for the purchase. The problem is that if the code does not take a discount, it doesn't register as being used. Does anyone know a workaround for this? The site is using ZC v1.3.5. Any help would be greatly appreciated. Thanks in advance!