You basically have to fill the sleeve image file with one color, and in case with the legs, you have to divide the two colors on the middle, like this in the image under.
And when you enter the game, you have to select the other color for the other sleeve on the suit for the jumper (as usual).
I've made these ones earlier today:
Manuel Fettner (2012/13)
(he also jumped with one white and one black glove in addition to this suit, I couldn't make this there)
Piotr Żyła (from Klingenthal in November 2013)
Kaarel Nurmsalu (Sochi 2014)
Simon Ammann with the asymmetrical red/white suit he sometimes jumped with in the World Championships recently. When I made this (just a test), a very thin red/white line appears on the sides of the legs (from the crotch and down).