It looks like it isn't able to be configured exactly the way you want it at the moment.

Other options are:
If you go to Scrolling>Tap Scrollings and select the "Scroll on finger tap only" it's allow you to use stylus to select, but then you kinda have to bash the touch-screen with your finger in order to scroll.

You can also use the d-pad to scroll (with or without tap scrolling disabled). I usually set it up with Down being a small scroll forward, right being a large scroll forward etc.