I noticed there's yet another way. Set it not as ACT controller, but Cakewalk Generic Surface. In that panel there seems to be an option for saying what kind of control each parameter should be, i.e. Note On, Controller, Incremental, etc. However this doesn't seem to respond to my MC at all. Also it only allows you to assign 16 parameters per plugin. The QuadCurve has about 26 knobs and switches. I'm trying everything I can think of. Almost ready to give up. 
 
My only option it seems at the moment is put the QuadCurve at the top of the ProChannel chain. The top module is the only one the Mackie Control can control at the mo since Cakewalk forgot to update the Mackie Control implementation.

Hi zoffmeister:
 
I looked at the User Manual for the MCU Pro and there seems to be no way to manually assign Standard MIDI CC Numbers to the controllers. The Cakewalk Generic Surface plug in and the ACT MIDI Controller plug in works great for controlling SONAR's track and plug in parameters, if Standard MIDI CC numbers can be assigned to controllers on your control surface.
 
If it is the case that Standard MIDI CC numbers can't be assigned to controllers on the MCU Pro, that is disasterous. I see that Mackie seems to be depending on a DAW software to support the MCU protocol, but I think it's lame that such expensive gear as the MCU Pro doesn't have the ability to assign Standard MIDI CC numbers to it's controllers. SONAR is reported to be lacking in efficiency as far as support for the MCU protocol goes. Really, it's not the DAW software responsibility to support the protocol of another company. It can get more users to use the DAW software, if a DAW supports a user's hardware, such as MCU protocol capable hardware, but it's not the DAW software responsibility. I always wanted to get a MCU Pro, but, now, I will no way get one because of this lack of functionality. I would be very upset with Mackie for not having the MCU Pro support the assignment of Standard MIDI CC number to it's controllers, if I had a MCU Pro. This ability is something all MIDI gear should have. I feel for you, and I'm sorry you're unable to get success with your MCU protocol gear efficiently controlling SONAR's track and plug in parameters.
 
I have a Keystation Pro 88 which has the ability to assign any of it's controllers to Standard MIDI CC numbers. I use the Keystation Pro 88 with ACT, the Cakewalk Generic Surface plug in and the ACT MIDI Controller plug in to control SONAR parameters for tracks and plug ins. I was wondering if you're using the Keystation without problems to control SONAR parameters, because I am using the knobs, sliders and buttons on the Keystation Pro to control SONAR's track and plug in parameters with great results, including the ProChannel EQ (using 16 knobs on the Keystation to control the Prochannel EQ parameters).

Hi Thomas. I have never used any of the knobs and sliders on my Keystation Pro simply because I have Mackie Control and two Extenders. The MC works great for all track and transport type stuff. It's just the plugin implementation that was lost when Sonar went to X1, 2. 

OK I see.
 
Still, it's a bummer you can't manually assign Standard MIDI CC numbers to the controllers on the MCU Pro. If you could you could use the Cakewalk Generic Surface and/or the ACT MIDI controller to control the plug in parameters, including those of the ProChannel modules.
 
If that Keystation is gonna stay in front of you like it is on your avatar pic, you might wanna consider using the knobs, sliders, and buttons on it to control plug in parameters. When you setup the Keystation to use the Cakewalk Generic Surface, ACT will be available so that the knobs, sliders, and buttons can be used to control parameters for whatever plug in has the focus. And when you use ACT to assign the controllers on the Keystation, SONAR will remember the assignments and use them for any instances of the plug in, in any project. That probably could come in handy for you. It's just a thought I figured I'd mention.
 
In case you hadn't known, Cakewalk has recently "...published the source code for several production control surfaces that ship with SONAR to the open source Cakewalk community" (see here: http://forum.cakewalk.com/FindPost/2993349).  That includes their source code for the Mackie Control Surface. Maybe some developer in the Cakewalk community will fix it, so that Mackie Control works properly in SONAR to control plug in parameters, as well, and share the fix with the community.
 
Goodluck to you, and cya around.
 
 

Thanks Thomas. I'll experiment trying to set up the Keystation Pro with ACT. I suppose it's lazyness, but I have the Keystation on a pull out sliding shelf. I never pull it out any further than far enough to just expose the keys. I have all these knobs and sliders I've never touched. How wasteful of me. 

I use an m audio oxygen to do this with remote control and the learn function.
its almost just like the key station pro 88.
 
I also have a control surface a vs 20 for faders, knobs, exc.
but I use the key controller for this, its easy. makes controlling it a breeze.