Thanks Spade - me likey too.
DJTUNRZ - get some spray adhesive and tack it to the jacket. Cut your shirt out, spray the back, and then apply to the jacket/vest. You need to use the spray adhesive so the back piece doesn't "flag". After it's dry, sew around the outside to double secure. I use an industrial Juki machine, but the little 40$ cheapie from Walbangers will do the trick.