o-blog (helpwith autocompletions)

[Catonano]

Hello people,

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 )

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