Featured image not showing in RSS / mobile

Hi folks,

I’m trying to “mobilize” my website by using https://www.google.com/gwt/x

The problem is that the featured image doesn’t appears. Yes, I’ve followed this tutorial, but still no luck.

Here’s the link to a demo article, and here’s the link to the RSS feed.

Please give me a hand here, I’m really out of ideas.

Thanks a lot!