I have an old Midi Casio keyboard, model LK-42, i hooked up the midi cables from the in and out on the keyboard to my Mbox 2 in and out. On Protools 7.4, I added a Instrument track, and when i play the keyboard, i see the keys being played on the track, but i can't hear them through the headphones nor during playback. Protools doesn't even say anything about the keyboard existing. Any advice?!?!?!?!?!