We are a distributor, looking to expand sales via electronic marketing.  I don't see any forum/category that mentions sales, so here I am

I am looking for the SAGE 100 solution for offering a promotion code via email or postcard that ONLY applies the discount when redeemed.  At the time of ordering, the customer would give the code and receive the discount.  After the promotional period, we would be able to run a report and see how effective our marketing effort was.

I can set up a promotion with a code that offers a discount for a specific time period, but it seems to apply to every sale of that item.  Is there a solution for this available for SAGE 100? 

I am not finding anything in the documentation or forum that addresses this.  Can you point me to the solution?