Ability to search for calendars directly from Confluence search box

A customer requested this:

One of our biggest demand since we began to work with TC is the enabling of fulltext search for calendar entries - able to search for calendars directly from Confluence search box instead. They are just normal wiki content that we expect to find.

We just want to see calendar entries too when using the fulltext search. An option to restrict the search results to calendar content would be fine too (What field in the dosearchsite.action). Actually there only options like pages, blog posts, comments, attachments