My viewing of CARF's models would say they only have enough steering power when the model is moving too. I don't remember seeing the nose wheel work standing still and as Ali says they use full movement each way as they are doing any manoeuvring.
The other option I thought of would be a worm drive cylinder on the steering. Whether that would act fact enough I don't know, but someone would have to design a circuit to power the drive in each direction.
The steering cylinder from memory is quite small, so maybe just not possible?

Dw