There are other alternatives to explore as well. Jammer Pro and Band in a Box work well if you do not need real time ( live )accompaniment. each has a feature limited demo that you can try out. Frank uses something else too, Hi Play Pro maybe ?

There is also JMT orchestrator, and it does open up a midi effect in Sonar. Not sure if it would work in Cubase, possibly it might with the mfx wrapper used with some of Musiclabs programs.

AJ