I suspect that a great deal will ultimately depend on how much the BMW engineers have done to the map to suit the physical installation in the Aero.
It's possible that they haven't changed the sensitivity map for the pedal position sensor from the standard BMW installation - which means that if the Aero installation has a different pedal arrangement with a different range of movement, then the 'dead zone' could be caused not by the map, but by the revised pedal layout: a different arc of movement would generate a different rate of movement in the pedal position sensors.
If you have a look at the hinge end of your throttle pedal, there will be some kind of linkage to convert the essentially linear movement of the pedal to the actuation required by the pedal position sensors - which are almost certainly going to be simple potentiometers, and thus probably with a rotary motion. If there is some kind of adjuster here, there may be a mechanical fix to the 'dead' zone at the start of the pedal travel - it may be as simple as adjusting a pedal stop screw. But as I said, I haven't had a close look at the exact way this is done in the Aero, so I may be blowing smoke here - I'm just extrapolating from my general knowledge of how FBW throttles work, and how it has been implemented in my car.
The danger here of course is that you adjust the pedal stop position to give a nice pickup, and then you find the pedal pad itself is now in an awkward or uncomfortable position for your foot.
With my 4/4 VVTi conversion, I found I had to bend the arm about quite a bit to give me the positioning I wanted - fortunately easy because the shaft itself is mild steel. But what's fine to do with an out-of-warranty car with a completely non-standard engine conversion may not be wise to attempt with a rather more valuable Aero, still under warranty :-)
