Didn't I tell you how in your other thread?
The second way is to have Audition monitor the input. To do this, you select the input to record and output to monitor to, then arm the track to record. Make sure Audition's monitoring is internal, it is in the box at the lower right part of the screen (im at work atm, so I can't be more specific). The advantage to this type of monitoring is that you can feed realtime effects, for example, studio reverb, straight into your headphones from the input. You will need to have low enough ASIO latency to monitor real-time in audition, which you should be able to change in your cards ASIO settings.
You need to lower your ASIO sample size, or use your card's monitoring rather than Audition's.