Thank you for your reply.
I think I was not clear enough in my first post, however. I have everything set up correctly, and I have successfully used CCs to control all of the other parameters on the Virus. It is just this one specific case that does not work for me: MIDI CC 38, controlling Ring Mod Mix.
I was hoping someone could do a test on their Virus to see if it works for them or not. If it works for someone else, then it is a bug with my unit, and if it doesn't work for them, then it is a widespread issue, which I'd like to report to Access.
Could anyone confirm this? Thanks so much!
ps. Original Virus TI desktop, running 5.0.3, receiving MIDI through USB.