Best way is to write on something with a pen (the same if possible) and spray some lacquer on it. I know that on a guitar I painted for art at school I tried to spray had permanent marker on it, but the acetone in the lacquer (or whatever part it is) dissolved the marker and it ran, and you don't want it to do that. Try it on some scr@p or something first. That's ALWAYS the thing to do when you are even a little unsure about something.