o-blog (help with autocompletions)

[Catonano <catonano@gmail.com>]

Hello people,

I'm  using the org mode that comes bundled with the Emacs installation
in Fedora 19, I think it's Emacs 24.2.x (I'm writing from another
machine)

I'm playing with o-blog (on top of org mode) and I'm editing the file
"sample.org" (here
https://github.com/renard/o-blog/blob/master/example/sample.org )

On the base of  what I read here

http://orgmode.org/manual/Completion.html#Completion

I tried to let the thing autocomplete this partial word

#+o_blog

then I hit C-M i (for calling the autocompletion) and I was informed
that no completion was available for that symbol

So I wonder: how is the set of possible completions calculated ?

Why the keys related to o-blog aren't there ?

Can I improve this situation ? How ?

Thanks