For those who still cant use this skin or the v1 skin when playing a game due to the "cannot start a modified game" screen
1) Download the custom gamedata mod from the srb2 wiki. 2) Add both files to the addons folder. 3) When launching the game, enable the character pk3s and *then* the custom gamedata mod. This will restart the game and will allow you to start a file with any mods you want.
You'll have to repeat step 3 any time you launch the game.