Reply to Question about which soundcard to get???

I just traded my 4trak for a Behringer ddm4000 and a Novation Launchpad. My setup consists of 2 Launchpads and 1 DDM4000. I want to use one launchpad as deck A and the other launchpad as Deck B. I want to use the mixer as the mixer, not as a midi controller. Can I use an Audio 2 Dj and just route the audio through the mixer? Or should I get a different soundcard? I hope that made sense...If not, I made a VERY DETAILED drawing of what I am trying to say.

A2DJ LP DDM.jpg