How do I provide a revenue passback macro for retargeting ads?

[dlowepriceweber]

We are working with a company to do retargeting ads and they have asked provide them with a "revenue passback macro" so that they can develop/provide us with a conversion pixel to track dynamic revenue values so we know how much sales came directly from the retatgeting ads. I am not sure how we go about providing them a "revenue passback macro".