Bc2000 (for the BCF2000 & BCR2000)

I'm guessing several of you will be using the BCR2000 with ableton 
live, maybe you could help. 

I want to control the pan of a channel with as few buttons as 
possible. I prefer not to use a rotary, since I want quick access to
specific settings, left/centre/right 

I've assigned one button and this goes from hard left to hard right &
back. I've used another to centre it. Could I use a single button to 
go left, centre, right and back again? I realise this might be an 
ableton issue rather  than the BCR, let me know if this is totally 
off- topic!

If anyone is willing to swap ableton ideas on a one to one basis, 
that would be good.