Why not just remove the battery from the TX when you want to peak charge and or cycle the battery?

NiMh will require several charge/discharge cycles to operate at capacity.

Most modern TX's have a diode in the charge jack circuitry, this protects the TX from incorrect power input and damaging components. It also prevents chargers/load testers from reading the pack voltage, herein lies the problem. Power can be introduced or passed into the TX through the diode, but is limited to one direction much like a one way check valve.