A work-around that might work is to install the demo of Breakaway *Broadcast* along with Live, and make sure to install four instances of it. This should give you four pipelines, that you can route audio between.
I *believe* that if you then remove Broadcast and leave Live, the pipelines should still appear.
I have a stream* setup where the input is the line input device of the professional sound card, and the output is Pipeline 3. EdCast takes the audio from Pipeline 3. I can then listen to the output by telling Windows 7 — under the volume control properties — to listen to the device on whatever I want, say, the sound card output itself, or event the front-panel headphone jack which runs on the onboard audio.