Use volume slider as horizintal scroll bar?

Hi there, I'm using the "[Example] Volume Slider for Android" by Bipolar games which they posted and its great, thanks for sharing!

The way it works is great so I tried to use it to scroll where the slider stays still but the bg moves.
It doesn't seem to work possibly breccias the last touch co ordinates get confused when the bg moves?

Just wondering if there's a fix for this or I should just do custom scrolling where the bg is active and just moves itself rather than using the inbuilt scrolling?

Thanks.