MIDI bug

I've downloaded the demo and testing it out with my Kawai MP8, but there seems to be a bug with the MIDI. I have the Kawai plugged in via USB to my mac running Mountain Lion. I load up Notion3 and set up a new doc with External Midi, Port A Channel 1. In preferences I've set the midi input and port A output settings to the Kawai.
I then select Step Time MIDI Record and press a key on the Kawai and nothing happens. If I add notes using a mouse, it plays the note on my Kawai.
I switch off the Kawai, relaunch Notion3 and once it's loaded I switch the Kawai back on. Now I can input the notes via the Kawai, but when I click Play it doesn't play back on the Kawai.
Any ideas as to how I can get both MIDI input and output working at the same time? I don't have this problem using a trail of Sibelius.
I then select Step Time MIDI Record and press a key on the Kawai and nothing happens. If I add notes using a mouse, it plays the note on my Kawai.
I switch off the Kawai, relaunch Notion3 and once it's loaded I switch the Kawai back on. Now I can input the notes via the Kawai, but when I click Play it doesn't play back on the Kawai.
Any ideas as to how I can get both MIDI input and output working at the same time? I don't have this problem using a trail of Sibelius.