Taxonomy visibility: Only access [term], [term-raw] and other taxonomy elements in editing mode

Hi guys,

I want to do something simple. I got page_title and tokens.

My node is tagged with a taxonomy term, let's say foo.
All I need is that the page title becomes foo for the nodes of this type.

Easy? Well, I thought so. I just filled the field corresponding to the node type in the page title admin area with [term].

And so what? When I see the page, it has no title. But when I edit it, it has the good one.
Do you know why the taxonomy elements are not availlable when I consult the node and available when I edit it?

Any idea?

Thanks in advance guys.

Regards.