We'll create fresh WordPress site with WP Microdata installed. You have 20 minutes to test the plugin after that site we'll be deleted.
Lets you add blocks of microdata using shortcodes.
[microdata type="http://schema.org/Article"]
[md_item prop="articleBody" element="p"]Lorem ipsum and so forth[/md_item]
[/microdata]
Simply add the shortcodes using the bundled TinyMCE-plugin which is placed in the visual editor.