Just to show how easy it is, here's Java (and maybe C++, I don't know) code to turn a Victor object victor into a relay based on Joystick object joystick buttons 8 for forward and 7 for reverse (the left buttons on the base of the Attack 3).
Code:
if (joystick.getRawButton(8))
{victor.set(1.0);}
else if (joystick.getRawButton(7))
{victor.set(-1.0);}
else
{victor.set(0.0);}
I'm at home, so I haven't tested this code, but it should be enough to get you started.
Since you're still using a speed controller, you can have it ramp up over a period of time, so you don't have as much of a current rush. You can also have your rate be less than full, or even different rates between forward and backward.