"There is solution for everyone to use whatever 2 soundcards u have with Traktor, it is Cubase SX that has asio drivers in it, so after installing this great software u should choose asio media in sound card box in Traktor, after which u will be able to choose one sound card as master and another as monitor.
Here is link for Cubase SX demo with which u'll be able to use asio drivers^^ (33mb for download)