need help with problem using pitch bend wheel in Logic 8

Hello,

I just upgraded to Logic Studio to compose an upcoming film score with, and I've run into a problem. Previously I used GarageBand and the Symphony Orchestra Jam Pack with my 66-key M-Audio Keystation MIDI keyboard, using the pitch bend wheel for string crescendos and decrescendos. It's made a huge difference in lending more performance emotion to the piece. Logic 8 is an incredible improvement over Garageband, but for some reason the pitch bend wheel no longer works to control the volume/expression of the strings. This is also the case now with Garageband (even though it worked fine before installing Logic Studio). I did a lot of research to try to figure out why this is, and from the best I can tell, it seems like it has something to do with one of the MIDI controllers needing to be reassigned.

The pitch bend wheel works fine to bend the pitch on other patches, but for the Symphony Orchestra Jam pack, it doesn't do anything.

In case this helps, I tried recording with the pitch bend/expression wheel on one of the Symphony Orchestra string sounds in GarageBand, and although there's no difference in volume when I turn the wheel as I record, I do hear the expression once I rewind and listen to the recording. So apparently it's recording the signal (at least in Garageband), but somehow I can't hear it when I'm performing. I'm not sure if the same is true in Logic.

Any help would be greatly appreciated—I need to use those sounds for the score, and I don't have too much time before I need to get started. Thanks!