Direct link to purchase Marketpress item

Here is the scenario.

Our Marketpress install has various instant download / PDFs for sale.

We have somebody that wants to resell our “buy and download” products, but they want it to be seamless through their own website.

We would need to track who the purchase came from; we were thinking with a coupon code so we can invoice them later based on the number of coupon processed.

The process would be something like,

– the end user buys the product from our client’s website.

– The client would process the payment through their own PayPal.

– the client would send a link to the end user to download the product from our website

– our website would track the download based on the coupon code used so we can tally and invoice the client on a quarterly basis.

I’m wondering if using the affiliate plugin would work somehow.

Any thoughts on accomplishing the above using the above method, or another method, is most appreciated.