Manually add Pingbacks to Wordpress Posts or Pages.

Adds an options page in the Comments menu.
You select on which Post/Page the referring Link should appear, add the Site name and URL, then paste the referring text.
Plugin on Wordpress.org

- Installation -
1. Download the latest zip file and extract the 'add-pingbacks' directory.
2. Upload this directory inside your '/wp-content/plugins/' directory.
3. Browse to the 'Add Comments' page on the Options menu.

download here