In case you are reading this, what was happening in my case was that the blog wasn’t public yet – I was browsing it by modifying the hosts file.
It looks that the communication must be possible in both ways, and I didn’t recall about it after a while :-).
Thanks a lot for your support and best regards.
Forget what I said, it works like a charm (I was just looking the photos in wrong order.. my mistake :-).
