S is probably a sport mode with higher revs or something. B I don't know, I'll post should I find out.
EDIT: S is sport, B is for braking. It increases the use of the engine brake, likely for going down hills. Since this CVT has no gears to manually choose from, you need this to adapt to the individual situation.
Okay fine, but how do lets say, a LHD Cherokee or a RHD Nissan Patrol 4200 diesel, both of which have REALLY LOW mounted alternators, go unharmed through deep water? :s
B could be some kind of engine braking mode for the transmission. Prius has a similer option that uses the energy from engine braking to recharge the hybrid battery and is signified as a B on the gear lever.
EDIT: Interceptor beat me 2 it. I should really read threads before posting