Yup.
The background image width then needs to be set to 750px (750x10px is a good number). In the Main CSS, .page "background" add:
Code:
#ffffff url(/path_to_image/.gif) repeat-y top left
Change the background color (#ffffff) and set your image path. Then in StyleVars you may need to change your Spacer size so that the shadows of your background shows fully.
If you need further help let me know.