Scrollpane does not scroll all the way down

Hi there, i have a movieclip which loads external images, i then attach this to the scrollpane, then listen for when the last image has loaded, then i refresh the scrollpane like this

function panecompleteHandler(event:Event):void {
//trace(“scroll pane refreshed”)

For some reason, it doesnt let me scroll ALL the way down. it leaves sort of 3/4 of an image unviewable. Is there a way i can tell the scrollpane to scroll down a bit further than it does?