Installed applications like soundjack use the soundcard directly and input/output the samples to and from the network.
If you want to use your DAW or other software on the PC in parallel to soundjack, you might want to experment with rogueamoeba.com/loopback
or the other product from same manufacturer, audio hijack.
We want to collect succes stories, so here are some DAWs we want to test in the future: