Bama,
Open up the sidewinder software, edit your profile, and click on the tab on the top right corner that says "settings". You'll come to a screen where you can set the deadband _and set what the twist axis does_
It is most usual to use the twist for rudder, so you should check the "twist handle to rotate in game" box.
However:
While the sidewinder software is very easy to use, I've found that in my set up, at least, it contributes to nose bounce. Personaly, I get a much better, smoother response by _not_ using the sidewinder software, and getting used to using AH's built in stick mapper, which gives you many more button functions, and a much better control response.
You lose the "shift" button without the sidewinder software, but if you use the shift button to change stick sets, you get four sets of buttons ínstead of two.