Repainting gauges?

I'm doing a repaint of the default B747-400 in FS2002, and I was wondering if you can actually repaint the gauges for the Virtual Cockpit? I know a lot of the textures for the cockpit can be found in the 'texture' directory of the aircraft, but I've noticed there's certain bits of the gauges which are not in there. So I'm presuming these are contained in the Gauges directory instead? Unfortunately, these are not in BMP format, so I can't alter them directly. 
Any help much appreciated!

Any help much appreciated!