Its not posdible to fix that.
On the skins up to f1 2012 it was possible.
In order to provide skins with a higher quality without having to increase (double) the size of the skin and therefore decreasing performance significantly for console users, codemasterd mapped the cars differently. Areas with only one colour (f.e. many areas of the ferrari that only were red, no sponsors on these parts) was made to a small red box.
That saved space in the file so the actual sponsord could be increased in size.
Some parts of the skin are the exact same on both sides of the car, so they only designed one side. The other side used the same texture. This saved half of the space used in past titles aswell, again smaking room to increase sponsor logos and therefore increasing the resolution.
Codemasters did not intent the game to be modded. Yet we still managed to do it.
Problem: If you re-skin a car, you might need to put a sponsor on a area of the car which was an area which could be mirrored beforehand. We cant change the mapping, therefore our new logo will be mirrored automatically.
Skinning got difficult because of that, compromises must be made, either setting the logos on a different, non accurate position of beeing find with having on side of the car with mirrored logos.