Can't help you on finding a layer, but I do believe there are paintkits around for these birds, check avsim and the like. I've found that a good paintkit has all these things and makes life a lot easier. You'll need a program that support layers, and if it has to be freeware, try the GIMP:
http://www.gimp.org/Note however that the default aircraft are not very good to repaint as some of the textures are mirrored on both sides of the aircraft, so you'll get weird letters...
For more info on repainting, and lots of tutorials, fonts and other things, look here:
http://www.simmerspaintshop.com/Good luck!
jankees