I've done this numerous time using nothing more than multi-pads, triggering the chord changes with the left hand by turning on the accompaniment button, but not actually triggering the associated style file, then turning the left layered voice, which can be strings, choir, etc..., but just enough to enhance the overall quality a bit by adding some fullness, then playing another instrument with my right hand, such as a grand piano. It really works very, very well and provides that subtle atmosphere you wish for some environments, especially when you add some light, quality vocals in the mix.

Good luck,

Gary