Ecommerce Tacking for MarketPress Pro (PayPal Express)

My Marketpress site isn't tracking Ecommerce data. I believe I have everything set up appropriately on Google Analytics and on the Wordpress site.

I have "Yes, an E-Commerce site" selected.

I seem to be tracking all other visitor activity just fine. I'm tracking views to /store/shopping-cart/confirmation/.

Is there something that needs to be setup on the PayPal side of things?

Thanks in advance for any help you folks can provide. (:

- Michael