I just purchased Marketpress and installed it on Headway (newest version). It's just a mess. I don't have any of the pages I need in my Visual Editor. I was using WP Ecommerce and had one product that I imported, however, it's keeping the settings of the WP Ecommerce product and not letting me change the design or functionality in the Visual Editor, it stays with the WP Ecommerce settings. I don't want to delete WP Ecommerce until I know this works, but right now it's a big mess.