I have the Eucon adapter license from steinberg. The Eucon Adapter is not showing up in the Cubase “device setup” page.
I have it working in Cubase 32bit only right now.
I am working closely with Euphonix tech support and I will post when I have more.
Currently Eucon Software is compatible with 32bit apps only.
This is from Euphonix support:
“64 bit apps aren’t supported with eucontrol.”
They did not mention when there would be 64 bit support.
After waiting 3 years I finally went a bought an MC MIx today, what an absolute mess trying to get it to work 
really…either Steinberg or Euphonix should be ashamed of themselves, we’re talking about expensive hardware/software here and it’s just not working after a 3 YEAR WAIT FOR DRIVERS…
Maybe Cubase 6 will be a different matter but as I’ve spent all afternoon trying to get this to work with my current set up, I’m pretty P****d off
MC
well after another hour of reinstalling Cubase and then the euphonix drivers I’t finally sprung into life…I can honestly say that’s got to be one of the most difficult installs I ever done,and I’ve been building DAW’s and running a studio for over 10 years!!!
well onwards and upwards
looking forward to cubase 6 arriving next week
Marcus
So it seems the re-install of Cubase is the key to get it working. same here.
the reinstall of cubase and the reinstall of the eucon software did it in the end 
Marcus
I had no such issues with Nuendo 5.1 32bit. I just uninstalled the mc client (I was using the mac server workaround before) installed the new Win7 x64 driver and eucontrol package, and voilà - it is working better than ever!