IDs with Colons

I can't seem to get jQuery to select an element with an id with a
colon in it. For example:
given
<div id="test:id">Test</div>
$('#test:id')
and
$('div[@id="test:id"]')
both return no results. However, if I add "test:id" as the 'name'
attribute instead of the 'id', I can select it fine. According to
http://www.w3.org/TR/html401/types.html#type-name, colons are fine for
ids. Any ideas on this one?