Reply to Fast Track C600 Mapping for Traktor Pro 2

i obvously have the C600 but im trying to use 3 of the 6 line outputs to send from decks A-C to my External Mixer and controll the levels that way but i cant figure out how to do it since its an audio interface and all when have the sound source as the C600 traktor doesnt want to play or anythng and ts really frustrating does anyone know on how to fix the problem here?