Which model of Fast Track do you have? If it's the current one, I'd try the Direct Monitor function (button on the front panel) and effectively eliminate all latency.
That said, I've used several different M Audio interfaces and their ASIO drivers have all be fine with Audition. The first thing to do would be to download and install the latest drivers.
Beyond that, more info please: what version of Audition do you have, how have you set it up, which model of Fast Track, etc.
