You are not looking for a String. You are looking for a background gif
with a randomly generated URI that starts with an @.
http://ss3.gemtalksystems.com//files/SSFileLibrary/logo.png#top {width: 860px;height: 100px;background:
url(/files/SSFileLibrary/logo.png) no-repeat;text-align: right;}
http://source.squeak.org/@71EZe8u4CEHqlLcp#top {width: 100%; height: 50px;background: url(/@71EZe8u4CEHqlLcp)
no-repeat;border-bottom: 1px solid black;font-size: 0.73em;text-align:
right;}
In a web browser, access the Seaside config page and go to the Files
section. Find the gif that says "Squeak Development" and replace it with
a new gif that says what you want.
Chris