Help: reset scroll text

Hello

I’ve got few text.txt file which are dynamicly loaded into textfield…
I don’t have any problem with loading those texts or scrolling them down or up, the problem is reseting them when I load another text after last has been scrolled.

Problem: for example, when I scroll one text in the middle of text field, then I load second external text in to same text field the text appear in the same position as it was scrolled last text and so on.
Question: how do I reset those text when I load them???

script for up scroll

 
onClipEvent (enterFrame) {
if (scrolling) {
_root.mainText.scroll--;
}
}

script for down scroll

 onClipEvent (enterFrame) {
if (scrolling) {
_root.mainText.scroll++;
}
}

the instance name of textfield is “mainTextField”
the name of “var:mainText”