Post-Indexer, index tags from pages

Hello, I have a problem with the Post-index plugin.

I do not have a lot posts in my WPMU installation, but a lot of pages with tags.
Now I would like to have a global tag cloud and I already installed the global site tags plugin.

but the table wp_site_terms is empty, only when I write a new post with tags the wp_site_terms is filled. Editing or writing a new page does not do it. Although the pages are correctly indexed in wp_site_posts.

I guess the plugin does not look for tags in pages, can you help me adding that part?

Kind regards.