I think it would be very wise to add a servo to the manual valve to have the capability of shutting off the fuel flow to the pump. I have seen an ECU malfunction in the air, the fuel pump continued to run and the results were not a pretty site. The servo could be mixed with the throttle trim so that when you shut down the ECU the servo also closes the fuel valve. David Gladwin outlined this in one of the Jet International Articles. He used a cable that can only close the valve. The valve had to manually reopened.

I think this is a real smart thing to do...could possibly save an airplane.