Reported for: WPML Multilingual CMS 3.4.1
Select the Show post translation links option in WPML->Languages->Language switcher options.
It is possible to translate the This post is also available in: %s string, but its translations do not display in the front-end.
Our developers are aware of this issue.
Go to WPML->String Translation, enable the Auto register strings for translation option. That would display the translated string.
However this option might slow down your site. Read more at the Auto register strings for translation section of the String Translation document.