How can I preserve target attribute functionality in Drupal 7 overlays? They appear to always be overwritten with target="_parent".

I have added a link to the help text of a field. I would like to open the link in a new browser tab/window so that the user’s input in the form is not lost when following the link. However, the target attribute appears to be overwritten and the link opens in the same overlay.

Here’s the relevant portion of the help text:

 I agree to the site’s <a href="../../node/5" target="_blank">Terms of Use</a>.