You can scroll a movie clip. Change your broken apart text into a movie clip and assign it as the contents of a scroll pane. Turn off or on the scroll axis you want. You’d need to edit the AS in the scroll bar to sync it with the scrolling text that is not mirrored.
I don’t think raw text can be warped (it can be scaled out of proportion) so what you are asking would be impossible if your mirrored text is dynamically loaded.
Or maybe it’s not, actionscript is a wonderful thing…