Restrict border width to text width in a block element

I have an <h2> title into a fixed with <div> (238px). When this page is rendered, the browser manage line breaks into the title to make the text fit the width (238px).

But the width property of the h2 element is still 238px, no matters where the line breaks are.

I want to set a border-bottom only under the text, and not under the full width of the h2 element, and I don't know how to achieve this using CSS.

You can see what I mean here : http://jsfiddle.net/np3rJ/2/

Thanks