Dave Smith Instruments SYNTHESIZERS

Hi,

I recently started using a PEK. With the way I like to work, tweaking 
as much as possible in the MIDI realm, I would like to use combi mode 
to tweak the 4 patches while they are played side by side, and as if 
they were 4 mono evolvers... this way I can design sounds to work and 
mix together.   However, what I am finding is that while I seem to be 
able to fully tweak the first voice in the combi by pressing voice 1 
and then turning a knob, say, the wave shape of an oscillator.... i 
cannot change this parameter on voice 2, 3 or 4.  Is this something to 
do with the design of the synth?  Or is there something I'm missing.  
If it is the way it is designed, I find it more than just a little 
annoying.  

-Collin