Markus - that's exactly the idea I was thinking of.  Transmidifier looks like a good one, a bit more modern than MidiOX!

Rob from Sydney
Is something like midiox an option, where you can remap the input data before it hits sonar? I don't know if there's any 64 bit equivalents, or whether it doesn't matter since this would run outside of sonar anyway.

It would function similar to the reaktor example above.

I first thought of MIDI-OX because it has the re-mapping built-in. But when I went to test it, I couldn't get it to work.
I was using 7.02, old but still current.
 

I'd use Midiox, running as a stand-alone apllication between the hardware controller and Sonar's MIDI track to handle this sort of job. It works fine woth Sonar in 32 and 64 bit Windows, the main thing to watch being that the routing is set up correctly so that Midiox receives the incoming MIDI, converts the CC number then outputs it on a port the Sonar MIDI track sees as its input.

Simply assigning a synth control other than the synth's modulation wheel function to CC1 may cause problems - CC1 is the MIDI convention for mod wheel, so using it for something else is likely to make the mod wheel operate as well as the desired control. Unless the synth can be configured so CC1 doesn't control the mod wheel any more, of course.