We've put in Fantasos as a back-end, so my thinking is based around its capabilities - and in this application, you could get your partner to sell them a 'membership' to your webpage where they exchange their emails / names to download the product.

Or they could send an email with a link to your download page (requiring a coupon code, name and email fields).

That way you get to see every sale, and you capture emails.

With our back-end, there's an option to allow you to see the details - or integrate to add them to an autoresponder list - but I'm unsure whether this is legal in all territories.

Of course with a good back end system, you'll get real-time updates of your sales too, which should give you some confidence that you're seeing all the sales - but I have to say I agree with Valeriu - If you don't trust 'em, don't work with 'em.

Warm regards,
Philip Greenwood