Marketpress Feed Products by Categories

Hi there !

I follow this tutorial : (thank you WPMU dev Team !) but It’s don’t work in my case :

I want Marketpress Feed Products by Catégories on my sub-store. So if I use[]=product it works great and I’m very happy !

But if I add[]=product&product_category=myproductcategory


I just have one link with one picture of one product and all the category page in one “![CDATA[“

You can watch the result here :

(This link expires in 24 hours)

How can I have a list of all the products by Categories in my feed ?

Thank you for your help !