This is an interesting one. I have been trying to figure this out for a while and so far I can't do it.
I have a virtual instrument loaded into SONAR Its EastWest Play, but it could be any plugin...so that's not the point.


The plugin has preset parameters that I can choose to automate within SONAR and they all work fine. However there are some additional parameters that it doesn't have setup. These parameters DO HAVE Midi Learn capabilities. I want to map them to open/unused CC numbers and automate them. How do I do this? When I figure this out, its going to be awesome!
Thanks!

Do you have a MIDI keyboard controller with assignable faders, knobs(rotary controllers and buttons?  If so it is very easy.  Assign an unused CC to a either a fader, knob or button.  Then in the plugin click on MIDI learn for the parameter you want to control, move the fader, knob or button you just assigned the CC then click on MIDI learn again.  Now that controller will control that parameter.  Note you can do this to some degree with other MIDI controllers but I have found that a keyboard MIDI controller has the yields the most options.
 
If you don't have a MIDI controller then how you do this will depend on the plugin.  Some like Kontakt will allow you to assign a CC to a parameter without a controller.  Others may also have this option.  With these you assign a CC to a parameter then in Sonar write in your CC settings.  You can use the piano roll view to do this.
 
I hope this helps - good luck.

Use separate MIDI track (not an instrument track), pointed to the synth. Add "MIDI..." automation, some unused CC. Draw some value (normally you have already constant automation created). Put required control into "MIDI Learn..." state, and start playing. The control should be "learned".
 
If you want to add more CC automations, the procedure can "learn" not correct control. But you can add yet another MIDI track with single CC automation and mute all old MIDI tracks to this synth. That is just to "MIDI learn...", you can put all required automations into one MIDI track then.

If the CC you need isn't listed as an option, switch instrument definitions for the track. You may need to add the ones you need to a generic definition.
 
Regards,
Dan

Something else. MIDI LEARN settings are not saved with the session. Each time you close then reopen the session you have to setup the plugins Midi Learn parameters again. What a pain!