This has been passed onto me by my friend Ken. here goes -
Start off with a sheet of clear decal paper.
1. Give it a coat of Future/Klear/Pledge MSW (referred to as Klear from now on).
2. Spray it with the interior colour of the framing.
3. Spray it with the exterior colour of the aircraft.
4. Give it another coat of Klear.
5. Trim it into strips of appropriate thickness.
6. Apply the decal in the normal way.
I am actually going to apply the decal onto a wet layer of Klear rather than using MSSET.
This will take place on my Avenger in the next couple of days so - Watch This Space!