This took me a while to figure out but i finally found a solution.
If you click and hold on the mono icon bellow the fader you will get the option of L, R, Stereo and one other thing i think. Click on L and you will only hear the Left channel. You can then export this under file, export, export track (or region). Then do the same on the R (right) channel. Then import them back into logic and place them on two mono tracks. You can then pan effect automate them however you want.
That's pretty much what I said in my original answer, except.. you don't need to bounce and reimport, just process on the channel strip. A Left CS with a stereo file = a mono CS with a mono file made of the left channel only.
The only exception is if you need to do any kind of destructive editing in the sample editor - in which case you can do the following:
1) Select the audio file in the Audio Bin
2) Choose Audio File > Copy/Convert File(s)
3) Stereo Conversion = Interleaved to Split
You'll end up with two mono files (.L and .R) in your Audio Bin.