[nOobCrafter]

		/**
		 The vertical position of text in a text field. The scrollV property is useful for
	 directing users to a specific paragraph in a long passage, or creating scrolling text fields.
 
	 The units of vertical scrolling are lines, whereas the units of horizontal scrolling are pixels.
	 If the first line displayed is the first line in the text field, scrollV is set to 1 (not 0).
	 Horizontal scrolling is measured in pixels because most fonts are proportionally
	 spaced; that is, the characters can have different widths. Flash performs vertical scrolling by line
	 because users usually want to see a complete line of text rather than a partial line.
	 Even if there are multiple fonts on a line, the height of the line adjusts to fit the largest font in
	 use.
		 */
		public function get scrollV () : int;
		public function set scrollV (value:int) : void;

посмотрите в сторону этих св-в, там еще какието есть точно не помню, думаю поможет.