hey rivers - totally get why you want to do this... cthulhu comes to mind...
a word of warning though. i've got an x2 project with couple of instances of reaktor doing lfo and envelope-based control changes to different synths - so, 2 instances of reaktor midi output running into two different midi tracks on different channels for recording purposes. problem is, sonar confuses the two instances of reaktor and records the output of instance one on both midi tracks. i have to shut down all synths that enable midi output except for one when recording otherwise the whole thing is a mess. i'm still testing it out but you might want to give that a shot just to make sure your setup is running ok with it.
my config is
reaktor 1 cc 4 output-->> midi track a on channel 2
reaktor 2 cc 22 output -->> midi track b on channel 4
midi track a -->> rapture
midi track b -->> dimension pro
i'd be interested to know if you have the same issues with the plug you're using and would be more than grateful if you could check it out before i file a problem report.
cheers and i look forward to trying out KC at some point.