Continuous scrolling


I have a background to a game that i want to keep looping. I have a function that applies acceleration and friction depending on if the cursor is in front of or behind the main character (if its in front the background looping movie clip will accelerate, if behind, it will slow down). Because of this i need to make the background movie clip loop using action script and not motion tweening.

Anyone know how to do this, or any other suggestions??

Many Thanks