There is no problem with the brakes.
The problem is that whenever the brake pedal is depressed enough to close the switch that's mounted on the brake pedal, the engine throttle does not work.
I assume that this is the switch that operates the brake lights too.

My "Mitchell on Demand" wiring schematics show a wire from this brake switch that goes to the engine computer.
I can only assume that the car is designed to act this way, or else this feature was added to keep the engine from "running away" if there was a problem with the throttle module....sorta like a fail safe...so that you could atleast stop the car.

With the engine running and my foot on the brake pedal I can depress the throttle (gas pedal) completely and there is no engine response...none.
If I keep the throttle depressed and take my foot of the brake pedal, the engine will increase RPM's.
It's not the brakes holding the car back, it's a total lack of response to the throttle.

The danger that I see is the engine's response to a full throttle has a short lag time. If use the brakes to stop on a hill (or any time) the engine will go to idle....it doesn't matter whether I'm depressing the throttle or not.
If I release the brakes and press the throttle, the lag time in the engine speed increasing keeps the engine from holding the car on the incline, and allows it to coast backwards until the engine responds.
The problem is in the Throttle, ot lack of response to it.

I'm just wondering if this common to all of the S70 Models with the "Fly by Wire" (Throttle Control Module) set-up.

I hope that's clear.
Thanks for your reply.
steve