Embedded and 404

Embedding a webpage that returns a 404 (ex: www.vaadin.com) causes vaadin app to load the docbase path. How do I prevent this from happening and just showing a 404 error just like it would embedding it straight into an iFrame.

Vaadin code:

Embedded e = new Embedded("Vaadin web site", new ExternalResource(
                "www.vaadin.com"));  //note malformed because http is missing

Equivalnet HTML code:

<iframe src="www.vaadin.com">
  <p>Your browser does not support iframes.</p>