record playback device

Hello, im using wavelab 6

I am trying to record playback audio (web media / video games / etc ),
I am using my device as the playback / record device as the audio input, but
I am receiving no sound? I use a Traktor Audio 2 external sound card, with the
audio played back on channel A. The card is USB and there is no other equipment
in the loop.

I am wondering if i am doing something wrong? I can record the audio using my onboard sound,
but I cannot get playback audio to record with the card, although it PLAYS audio
just fine.

Any help would be appreciated!