The data: URI kitchen page - allows you to create the BASE64 encoded version of you’re 16×16 icon.
RedMonk Google Coop search page - this is the page and I used to generate the URL I pulled apart for the OpenSearch XML file.
RedMonk’s OpenSearch XML file - the XML file that we use for configuration. Feel free to use it as a template as well ;>
One thing I neglected to mention is that the OpenSearch template provided on the Firefox page is invalid XML: it needs the first line to <?xml version="1.0"?>. You can see that in the RedMonk OpenSearch XML file.
If the screencast and files don’t help out, feel free to contact me and we’ll see what we can do.