ScrollPane - knowing direction of scroll

Heya,

Is there a way to know which direction (up or down) the scrollpane is scrolling?

There is a function that lets you know that you are infact scrolling. For instance, you can attach the code:

on (scroll){
// do stuff
}

…to the ScrollPane. But it doesnt discriminate between directions.

Isnt there something like:

on (scrollUp){
// do stuff
}

…etc.?

Thanks