You could find a thin piece of sheet metal, bend an angle in it, drill a hole in the short side of the angle. Take your blinker off, put the piece of blinker tubing through the hole you drilled, and put it all back together. That would give you a flat plate leaning up against your blinker stalk to put you DOD sticker on.
I think that should work, I haven't actually tried it, my military time was up long ago.