Is it ok to install an ON/OFF switch using the brake's kill switch circuitry?

Hi
I have an electric bicycle that I like to ride without the motor sometimes and with the motor for the hills etc. However the only way to do this is via an ON/OFF switch on the LiPO4 battery pack. Firstly this is difficult to reach while riding and secondly I loose power to the cycle computer and lights. I would like to install a switch on my handlebar that allows me to turn off the motor (and therefore pedal assist) easily.
I was thinking I could use one of the brake's kill switches for this. I was going to install a simple on/off switch across the wires going to one of the brake handles. I believe the brake handle works with a small magnet that completes a cicuit when the brake is pulled, cutting out the motor. So if i install a switch across the wires, when it is ON it should complete the circuit and cut power to the motor. When it is OFF, as the switch is in parallel across the wires, then motor should work as normal and the brake's kill switch should work also.
Is this a good idea to do? Is there any chance of damage to the controller or motor with extended activation of the brake kill switch?
Any advice would be appreciated as I am a newbie at this am no mechanic/electrician.
Thanks
Hamish