Piz midi plugins might be useful as well, I use those a lot.
http://www.kvraudio.com/forum/viewforum.php?f=148
They are free. But they are not recognized as Cubase midi plugins, just as ordinary vst synth without audio.
The midiConverter3 plugin will load like a synth and can be cascaded to another instrument taking input from that.
I think it will do what you ask if you send CC46 it can create opposite CC49 for you.
One CC in and select another out, and reverse values by setting low higher than high.
Adjust thru to not block selected, but just let that through - and it creates the other as well.
I use Metaplugin (http://ddmf.eu ) to load a bunch of those together with a bunch of instruments for convenience.
Just drag the connections as you please - midi and audio.
There is a similar plugin by bluecat audio Patchwork that works in a similar way.
Just save as preset to reuse.