I didn't post here when you originally posted the unit, Aluminium, but I really like your recolorations. There all very nicely done. The white cross is just the civ-coloring. It looks like when Aluminium placed it in the game to make the screen shot, he assigned the unit to the barbarians. That's probably why the cross is white.
Thanks, Utah. @Cheezy: In the Poland campaign the german tanks had a white cross. I don't know why. Probably it was the pre-war sign. Later, of course, it was the typical straight black cross on white background. But that isn't the reason for the white and the dark green. I just needed a tank for my Austrian Civ. They got the white as civ-colour. So I did want a darkish camouflage to get a good contrast to the white cc.