This is a simple applet (actually a patch) that allows you to have up to 10 presets on the Squeezebox Radio instead of the normal six.
It requires installation of the Patch Installer applet first and then this patch is installed from there. Once installed navigate to Settings -> Advanced -> Beta Features -> Shortcuts. From there you can map buttons to presets 7-10 which were previously not an option. I map holding preset buttons 1-5 to playing saved presets 6-10, leaving pressing the buttons with their normal function. This does mean that setting the presets needs to be done via another method (eg using the web UI).