Here is a tutorial on how to install a scrolling background in WebPlus simply and using jquery.
First of all you need a call to the jquery library on your page. If you do not already have one, such as for a WP lightbox or other WP or third party object that uses jquery, then add the following to the <head> of your page:
Adjust the path to where you have installed the jquery.js
Create your scrolling tile image and save it as a png. (Suggested Size 600px by 800px)
Add the image to WebPlus using Tools > Site Manager > File Manager.
Add the following code to the <head> of your page:
Finally ADD the following just after the <body> tag and before the first WebPlus created <div>, You can paste over the <!-- Page Body Start --> that is there.