Yea, i know, I'm new to the forums but I've been lurking around for a month or so. But i noticed there is a lack of example of how to setup an infinite background so i decided to make one.
http://www.box.net/shared/6zvpp2e904
Although i have a feeling that I'm missing an easier way of doing this, but on the bright side it shows how to expand adjustable background scrolling to outside the normal layer "window"