WordPress Strips Classnames, And How To Fix It

WordPress 2.0 introduced some sophisticated HTML inspecting and de-linting courtesy of kses.
kses is an HTML/XHTML filter written in PHP. It removes all unwanted HTML elements and attributes, and it also does several checks on attribute values. kses can be used to avoid Cross-Site Scripting (XSS), Buffer Overflows and Denial of Service attacks.
It’s a good addition, [...]

why not?

does anybody know a way make a reverse-ordered — think countdown — ordered list without resorting to non-semantic (though ingenious) css tricks?
ordered list, lists, html, semantic markup