I have my casio px 5s connected to an old casio ctk-481 via midi in; im using the old casio to control the sounds of the casio privia px 5s, zone 1 is assigned to the keybard internal sound generator, and zone 2 is controlled by the casio ctk481. Everything its going well, but then i noticed that i cant control the sound of zone 2 with the sliders. Specifically, slider 3 is assigned to control expression for that zone, but it isnt controlling anything. But then when i select a different stage seting, i can control the fast rate and vibrato for the zone 2 with the sliders, without changing anything, apparently. Whats going on, why i can use the sliders in one case and not in the other one???? It seems that the sliders work in the second case because they are controlling a DSP parameter, wich can be controlled this way. As expression isnt a dsp parameter, it cannot be controlled that way. That said, i still dont understand why it happens, why the dsp parameter can be controlled and expression cannot. Is there a way to control expression of zone 2 (external device) with the sliders??? Do i need another midi cable, to connect the privia midi out to the old casio midi in, in order to do that??