Controlling initial scroll of dynamic text

ok so i’ve made a simple shoutbox with flash and php. nothing fancy, just something that gets it done. but i have one minor issue i have been dealing with for some time. i can not for the life of me find out how to make the dynamic text box initial scroll setting to be at the bottom. make sense? i figure it shouldn’t be that complex but i have toyed with all that i can find on textfield.Scroll and textfield.bottomScroll, but have had no luck. anyone have any ideas?