I'm having trouble understanding the chord structure here. Surely, the Ab in the C chord will give you C augmented, which predisposes the taking out of the 5th? Alternatively, you've got C2b6 giving the notes C D E G Ab. I can see where a realtrack might throw in the towel at this one. Without hearing the whole piece, it's impossible to say it won't work, but I agree with Ian - play it as midi.

ROG.