The EMC susceptibility of Airbus FBW systems was assessed years ago. It is not a problem.
If you really think that you will need to throw tankers around in 'the combat sky'...
... then reconsider your Conops first, perhaps.
The only times I've had to manoeuvre a tanker abruptly were due to ill-disciplined 'coalition' fighters which had failed to stick to their assigned levels in the ROZ.
The KC-767J is a very basic aircraft with just a boom and is only a converted -200ER. It was delivered 2 years late, for which Boeing had to pay a penalty fee. In May 2010, it will be 5 years since the first Italian KC-767I, also a converted -200ER, was supposed to have entered service. The KC-767J and KC-767I have a max fuel capacity of about 72 tonnes - about the same as the in-service A310MRTT.
The definitive KC-767A has yet to be built, let alone flown. If you can find a runway long enough in a country flat enough, it will allegedly have a max fuel capacity of about 91 tonnes - way, way less than that of the A330MRTT. The Italians, despite having already extended the runway at Pratica de Mare, are already concerned about the max fuel their yet-to-be-delivered KC-767Is will actually be able to take-off with in the Mediterranaean summer...
Whereas Airbus tankers are already flying and are in service with a number of air forces, Boeing still hasn't managed to sort out the wing pods or centreline hose system - pretty basic elements of a tanker aircraft.
There's quite a lot of risk attached to Bubba Boeing's Frankentanker, it would seem.