Switching between Logic Express instrument tracks from My Midi Keyboard.

I've assigned separate/different midi channels to Logic Express instruments and I'm trying to access each track individually from my master keyboard by switching through the different midi channels, but regardless of what midi channel I switch to on my midi keyboard I only hear the track that's selected in the arrage window in Logic Express. So for example, I have Acoustic Guitar on track 1 assigned to midi channel 1, Electric Piano on Track 2 with midi channel 2, and Bass Guitar on track 3 with midi channel 3. I have track Acoustic Guitar track one selected in the arrange window. When I step through midi channels 1, 2, and 3 on my midi keyboard I only hear Acoustic Guitar on track 1. Any ideas anyone.

Thanks,

Julian