Shopping Cart with Affiliate Tracking Capabilitities for Word Press

Hi,

After searching this forum, I found out that a lot of people recommend ECommerce Lite, Microshop and even open source oscommerce, XCart.

Is there a open source shopping cart with affiliate management ? Can anyone give some advices how to integrate this into wordpress?

I really hope I can get an answer here because I have been searching this for quite a long time.

Thanks