for both the Peugeot ION and the Renault C-Zero one can add the I-MiEV gears "B" and "C" by simply changing (or modifying, to save money) the gear selector & cover plates, as these both gears are absent for them by design (or rather: can't be selected as the gear shifter & cover plates physically don't provide the ability to shift to the positions).
I did not modify the selector plate yet, but took it out to put the shifter into "B". It worked, the "B" popped up on the display (I could also select "C", and it, too, would be displayed).
The selection of "B" seemingly turned my car into turtle mode: the car would not react at all to any input at the accelerator pedal (event when pushed down fully). It would just slowly start to roll, like it does in "D" when the brakes are released. I know that the acceleration is intentionally decreased in mode "B", but there was literally ZERO reaction to the pushing of the accelerator pedal. So there was no "decrease" - there was no reaction at all.
When I went back to "D" (still without the selector plate mounted) the car behaved normal again, and operated like it usually does.
This car is a 16kWh, 47kw ION first registered in October 2014 in Germany. Everything works marvelous, only 26 thousand kilometers mileage.
My thought: maybe Peugeot somehow additionally disabled the "B" and "C" modes, so one can't hack via gear selector plate? Maybe some microswitch, intentionally uninstalled fuse, etc?