My best anwser would be this: the paint finishes (material types?) are stored in text files, not in the actual PNG file needed for your livery. So if in a download package, the livery and decals text files are not included, it won't show your livery in the correct paint type.I don't understand the question.
1) Where are the paint finishes shown?
2) What do you mean by download area in the ACC game?
3) What do you want to accomplish?
Kind regards