I've created a custom scrollers for a dynamic text box; However, I have no idea how to make it work with actionscript. Can someone assist me please?

Okay, I'll take a stab at helping you. Put the textbox on a movieclip. Put
the movieclip under a mask. Move the movie clip up and down or side to side
with your scroller(change it's x or y value). You will only see the part that's
masked. By the way the movie clip that holds the text box can be larger than
you swf clip.