Just bought thew new map pack for gears of war 2.. need help!!?

today i purchased the snow blind maps.. i have been playing it on wingman for 3 hrs now and I havent had a single match using the snow blind maps i purcahsed.. why is that? i am very upset now because i purchased that i could not use it for.. can someone tell me why i cant play on the blind maps on wingman mode?