Hi prof
You maybe able to do something with getting the fuel switch to work in cfs2 if you have FSUIPC installed.
This s/w allows you to get into the command area of the sim and apply keystrokes (offsets?) to the sim which it will then respond to.
The graphic animation should still work ok because the fuel switch animation responds to the mouse.
FSUIPC will work with CFS1 and CFS2 however not all of the functionality as compare to FS2002 etc would be available but you would have to try it out.
You could maybe ask Peter Dowson this question on his site.
FSUIPC however WILL NOT WORK with cfs3 in any shape or form.This means you can never get any instruments/gauges to work that you build, you cannot extract any data to drive a motion platform, you can't even extract any of the gauges in software to extend onto a seperate monitor (VC only).

However I still love/hate cfs3 so I'll just go away and shut up about it.

Lets us know how it works out.

cheers
chuck