Can I have text in the background of a jQuery UI progress bar?

You know the kind I'm talking about don't you?

The kind that where color:white because the progress bar is over it, and color:black because the progress bar hasn't reached it yet.

I think I've seen that type of effect while installing software.

Also, what about a background-image, which works, except that it is totally covered up by the progress bar? I'd like for the progress bar itself to be a little bit transparent.