I’m trying to use my A-300PRO midi controller with Rapture Pro. I want to use the A-Pro control surface that comes with the Roland midi controller ( rather than setting up a whole new control surface as I have seen referenced elsewhere on the forums ). Has anyone ever got the ACT Learn function to operate reliably and predictably ( if so how did you do it ) ? For me it occasionally works, but then some rotaries will point blank refuse to “learn” new settings. Also, when I close out of Sonar and come back again all the so called learning has been lost. It is frustrating because it appears so simple in the on-line demonstrations of ACT learn, but reality doesn't seem to match the sales pitch. Any ideas  ?

Have you seen this thread in the Hardware section?
 
http://forum.cakewalk.com/UPDATED-Configuring-Your-APro-to-Work-WithWithout-ACT-m2181430.aspx
 
Very good content on what you are asking. 

FCCfirstclass ... yes, I have been through the other thread, but the length of the article is difficult to take in, and as soon as it starts on MIDI CC numbers etc it loses me. I'm also aware that azslow3 ( who posts in the thread ) promotes an alternative piece of software. I guess my point is that it shouldn't be that complicated to get the APro to operate synth controls in some logical way, yet by default they seem pretty random and the advertised method of adjusting them ( ACT learn ) doesn't appear to work properly. I know you posted in the other thread as well though, so was then one "aha" moment that you came across where things started to make more sense ?

In short, ACT learn works as described in the documentation till the configuration (in XML) is corrupted or you try to learn VST3 plug-in. Unfortunately, that happens quite often. So the rest is about several ways to either minimize or eliminate the risk using alternative methods.
 
Since plug-ins was not developed with control surfaces in mind (till NKS), there is no default "logical way" to map them. Especially taking into account that total number of RP parameters is far above the number of available physical controls.