I would like to add a new tab based on semantic properties of the page (I am doing this from my own extension). The question is what's the best way to do it?
The problem gets more complicated for an older revision of a page.

As I can see from the SemanticMediawiki database structure only the properties of the last revision are stored in the DB.

What are other ways to access properties?

The Factbox class does the scan of all properties for the currently displayed page (any revision), so in principle this could be done by means of some hacking.
But may be there are some decent ways to do it?

So once again, I want to do something (display or not display an extra tab) on the page for older revision of articles based on semantic properties of that older revision.
How can I access those properties for the older revision from my extension (from a hook function)?

Any hint will be greatly appreciated!