Using the software from
http://forum.cakewalk.com/FindPost/2991556 message in the thread I linked above
After installing LoopBe1 and PC73,
Add LoopBe1 to Midi Inputs in preferences

Then
1) configure the output of PC73 to LoopBe1
2) Add a synth, configure the input to LoopBe1
3) make sure input echo is enabled

play on