Text on dynamic field to flow from right to left


I´m loading dinamic text from rollover on buttons, with:

textfield_txt.text = "Example of text loaded on dinamic field"

But sometimes the text will be longer than the permitted field _width, missing some letters.

Is it possible to make the text flow, like a marquee or a news ticker, from left to right when the text is too long, and then go back and start again? I searched for it but is always use movieclips ._x changing, and I´d like to make it just the text to move.