.dvd is the file that Imgburn uses. The .xex reads wrong, they never got the key which could've made it doable , s,random padding, andsecurity sectors are not in the files for it to work with a flashed drive. It was Marketplace content/Games on Demand, which has never ran on anything but jtags/dev kits. Just like people are playing Dead Rising 2 Case Zero now, on a jtag.
Someone ran it through ABGX, it won't be too much longer.