Wellis,
I have never been able to get 2048 textures to work for me in FS9 so I am unaware what the secret is.
I should also mention, for any repaints anyone puts out, that the Modern and Classis texture names are different for the fuselage, fuselage inner, and cabinets and cabinseat bmps.
The texture sets are different of course because the cabins, seats, interiors, and some exterior parts are different. Therefore one livery texture set cannot be for both Modern and classic unless they are in separate folders and carry proper names.
Modern version: If you see fusemod.bmp and fuseinnermod.bmp, the set is for the modern version and should have a cabinseatmod.bmp
Classic version: If you see fuselage.bmp and fuseinner.bmp accompanied by cabinets.bmp and cabinseats.bmp, then you have a Classic version set of textures.
The two sets can co-exist if all these textures are in the same folder for a livery.