As soon as I'm done with my work, I'll try to help you out
Anyway the difference btw yours and that one is that you are using the original texture, he's using a custom image for the thumbnail background (or whatever its called).
Try using this string for the thumbnail bg: <texture>name_of_image_in_media_folder</texture>
I dont know if its wrong or not, but try anyway
I still learning - by my own (Just a few guys in this place will try to help you out, so dont count on anyone)
BTW, try exploring the XPR file to find out dimensions of the original image, or just deduce it from the code (The dimensions of the thumbnail)
Then make a PNG using Photoshop - Just create a blank square with the same width and height of the thumb, and add it some some shadow effects