From what I can tell you need to add it to the html includes section to appear on the header not a island.
Islands are generaly only for the right and left column,post content ads and under special external use.
Control Panel » Display Options html includes tab.
HTML and PHP allowed.
Shows at the top of every page.
In your case possibly a island was created and used in the html includes header section.
Blue Man Group
There is no such thing as stupid questions. Just stupid answers