[Nick La belle]

Set FCP up for multiple outputs:

Go to: Sequence Settings
Go to: Audio Outputs (tab)
Where no. of outputs says 2, make it 4!
In your case, kill the stereo pairing and select “Dual mono”
Don’t worry about the 0 or -3 thing.
Go back to your sequence, and use the grey area around the “Lock”
to CONTROL-Click and set the audio output of that track to 1,2,3 or 4.
Your not gonna downmix anything I presume, so it should be as simple
as that. Check your FCP audio mixer for 4 outputs, and make sure the “downmix”
button above the master fader is not checked.
All should be sweet!