I use X1b and it certainly controls Pro Channel. Just activate ACT on the VS and once you have a module selected in Pro Channel it will control it.
I found the assignment a little odd. You might be happy with the way they have it routed, but I wasn't
If you want to see how they have routed it, simply open the "VS Properties View" from the Controller module. Depending on what Pro Channel module you have chosen, it will show how it is mapped out.
But it's really easy to re-assign these with ACT. I just finished getting mine all setup yesterday.
Here's a quick "how to" for re-assigning if you want to do that. Any changes here will reflect in the "VS Properties View" as well.
1: Open Sonar and any project with an audio channel on it.
2: Turn on ACT on the VS-100
3: Open Pro Channel (any instance), and choose the module you want to work with (comp, eq or sat)
4: In the "Controllers" block of the Control Bar, make sure the VS-100 is selected and turn on Midi Learn
5: Highlight (left click) the function to control on the Pro Channel > Turn the dial on the VS-100 to control it (it likely won't move on screen)
6: Repeat #5 for everything you want to control in that module.
7: Turn off "Midi Learn". It will now say "x" number of assignments were touched, do you want to keep them. Save it and you are done.
Repeat this procedure for the other Pro Channel components if you want. It really only takes a few moments.