Camera up / Camera down (Look up / Look down) for Joystic / Controller users

I use a controller to play GW2. And, I can map certain buttons to simulate "look up" and "look down". The problem is that the cursor moves slightly up if I look up and slightly down if I look down. So, after a while, I loose my cursor off the screen. I don't know if this is a common problem for people who like to use controllers.A good solution would be to provide an option for a button that would look up, or look down. similar to turn left and turn right.