The News Manager Addons plugin provides several additional functions to extend the News Manager plugin, so that you can customize its output (currently, only the sidebar latest posts).
Note that this plugin is in beta.
Requirements: News Manager plugin 2.2.x or higher
Download: GitHub page (direct download: news_manager_addons.php)
Installation: upload/copy the file to your site's plugins folder. Make sure it is activated in GetSimple's admin panel.