Ok finally had time to go back and play with the C-11 some more. The pneumatic valve did not do the trick to get the attitude indicator working.
Required is the 4th toggle switch from the front, cleverly labled HORIZONT ZATACKOMER ....but when I used the one in the VC it did not do anything.
Given the choice I never open the 2D panel....so I missed it's working cousin on the pop up panel.
Maybe this fix can be added to the short list of things left to make this a perfect rendition of the airplane.
Cheers
Stefan