OK, I’ve found the System Actions plug-in trick in the global rackspace.
Unfortunately, it does not work when I try to assign a knob to PC to sweep rackspaces.
I found this topic : https://community.gigperformer.com/t/controller-transformation-for-program-change/8519/20
with an example file from rank13, but it does not work 
It seems I have the same problem as jbgermany in his topic.