A disappointing response from Steinberg on this:
I will definitively create an entry in our bugbase for this case.
But at the moment I do not think that this problems will be issued with a high priority.
The CMC series is discontinued and has been removed from the shop almost a year ago.
We keep the drivers up to date but at this point i do not belive that we have free resources to adjust the compatibility with Cubase versions, which has been release after we stopped the sale of the CMC.