Looking for a script to populate wp_site_posts of the post-indexer plugin

Only posts published after I installed the plugin are in wp_site_posts. I understand this is by design but was just wandering if anyone had a script that would crawl the database and populate wp_site_posts based on existing posts.

I search the forums but if there's an answer out there that I missed I'd love to be pointed in the right direction.

Thx.