How to create an illuminated tail logo

I have just managed to repaint my first aircraft for FS98, starting from a ready-to-paint no-livery freeware aircraft (a Boeing 737-800).
I am quite satisfied with the result, but I can't figure out how to add an illuminated tail logo (activated pressing the "L" key and visible at night).
I know it's a matter of choosing the right colours (some colours are visible in the dark) and specifying a substitute tail texture to use when the lights are on.
The problem is that this aircraft came with no such function and so I wonder how it's done. Is there a tutorial anywere?
I think that it's the .MDL file that must be modified, but it's not viewable in a text editor.
Any clue?
I am quite satisfied with the result, but I can't figure out how to add an illuminated tail logo (activated pressing the "L" key and visible at night).
I know it's a matter of choosing the right colours (some colours are visible in the dark) and specifying a substitute tail texture to use when the lights are on.
The problem is that this aircraft came with no such function and so I wonder how it's done. Is there a tutorial anywere?
I think that it's the .MDL file that must be modified, but it's not viewable in a text editor.
Any clue?