MID control of drawbars - channer issue

[cam2000]

Hi there - i have set up a UC33e to run the drawbars of the komplete hammonds. To do so, I assigned each drawbar using the parameter/value assigning, and then assigned the corresponding cc's to the UC33e (not quite - i had to add 15 to each one to make it work).
Now, they are all on channel 4. So, when I have the the hammonds on the 4th mixing channel of the mixer, they work fine. If I have the hammond on say the 5th channel, even if I assign that channel to listen to channel 4, the drawbars do not work.
Do you know why this is?

I might be able to work around it by ticking the route MIDI ccs to source plugin box, but, if I do that, I cannot then control the volume of the channels in the mixer (for which I have another patch on the UC33e set up to do.

Any thoughts?

Regards,
Cameron