I have attempted a repaint on the meljet 777 paintkit (because it was the only one I could open without an error) and all I did was make the textures really blurry.
You probably need a texture converter like DXTBmp to open & convert the textures before & after editing.
http://www.mnwright.btinternet.co.uk/programs/dxtbmp.htmThis is covered in most repainting tutorials.
The basic principle for repainting is the same whichever graphics editor you use. You obviously have to be familiar with the application itself to do the actual editing. It also helps to understand the different texture formats & what they're used for. I found a good tute on the basics here.
http://www.simmerspaintshop.com/forums/flight-simulator/646-repainting-fs2004.htmlMost of the suitable graphics editors have similar tools & features. Everyone has their own favourite methods & utilities for doing the work & it's not likely you will find a tutorial using exactly the same applications you have. This is one of the many repainting tutes posted on various websites.
http://www.calclassic.com/repaint.htmIt's using PSP7 as the graphics editor but you should find similar tools/functions in Photoshop & other advanced editors.
