I am posting this in case anybody else is having the same problem as me...
Anyway, I just spoke to the Swedish E-magic/Roland support people, and they tell me that it is in fact impossible to pan voices like The Big Spin, unless you change the effects routing to bypass the Leslie effect - which is stereo in itself and consequently not pannable.
It's a bit strange that nobody on the forum could help me out on this.
All the best,
Magnus