resistive braking for induction motor?
This won't work but you are close.  In your situation, the induction motor doesn't have any stator current, therefore the motor doesn't act like a generator.

However, all you need to do is introduce a DC current into the stator and the motor will come to a stop very quickly.  The rotor acts as a shorted turn in the presence of the DC magnetic field and converts all the kinetic energy to heat.  

Do note that you must NOT leave the DC current applied to the stator or you will burn it out.

There are commercial units that work this way and they all have a timer that shuts the DC current off after sufficient time has elapsed for the motor to come to a complete stop.

How quickly the motor stops is a function of how much DC current you feed into the stator.  Several Amps is normal but I can't give you a specific value - it depends on your motor.