But it does preserve the line breaks, only line-breaks are the same as whitespace in HTML, so they have no special meaning. Just look at the source of the web-page and you will see the line breaks are still there.

What you can do is replace all linebreaks by <br/> tags and you will get the effect you want. Or you could simply enclose the text in <pre>...</pre> tags or use a module like Formatter::HTML::Preformatted.