http://www.digidesign.com/index.cfm?...&categoryid=34
Can Command|8 and HUI (or another control surface) work together?
No, Command|8 must be the only MIDI control surface enabled within Pro Tools.
Command|8 may be used with non-MIDI control surfaces (D-Control, D-Command, ProControl or Control|24) with some limitations.
When used with Control|24, Command|8 faders overlap (i.e. duplicate) the left-most eight faders currently banked on Control|24.