We placed ours in the panel and several sources told us that this is an acceptable practice.
I noticed this card to be very sensitive to metal and electrical current and was skeptical at first. I am told that the vibration of a plane actually improves the functionality of this unit. I will let you know if this is the case or if we have to move this to the windshield brace. Here is a shot of our panel with the Vertical Compass card in the panel.
http://img509.imageshack.us/img509/466/img5f0391tu2.jpg
http://img509.imageshack.us/img509/6...0377jpgkj9.jpg
Pat Garboden and Todd Wiechman building in Wichita, KS
RV9-A 942WG (reserved) slider with O-235
RV9-A 942 PT (reserved) tip-up with O-320