Is there a way to get the banner background to center and not tile, while at the same time not restricting the page width?

I know I can use a static image as a banner, but we want to keep the banner image just text and the background the picture for a couple of reasons.

Im using the guildportal banner maker, it makes a banner background, and then superimposes the text ontop of that as an image.  It used to be (about a month ago) that the banner background would be default to center and if the page width extended past the width of the background, it would continue on eitherside with a black background.  Recently, however, the default was changed to tile, so if the page width is greater than the banner background image, the background image repeats itself.  I can only center the background image by restricting the page width.

The easy fix to this is to have a black banner background and have an image as the banner itself, but there are guildies who want to view the webpage on handheld devices and can disable the background image by disabling java, which is not an option if the banner itself is an image, not a background.

What im asking in a round about way, is, is there a way to return the default format of the banner background, supplied using the guildportal banner tool, to center instead of tile.

http://fate.guildportal.com

Thanks for taking a look, I appreciate the help.