Single Sign On with Multi Domains plugin


I just installed the Multi Domains plugin. It works great, with the exception of the Single Sign On feature.

If I log on a blog of the network, and then I enter the URL of another blog, I have to log in again. Same happens with Buddypress: If I am logged in in one blog, I can see the BuddyBar and the list of blogs in my network, but if I click on any element of the Buddypress social network or any blog, I have to log in again...

Maybe I didn't really understand what Single Sign On means in the context of the Multi Domains plugin. What I would like to do is to make sure that once a user logs in a blog, he is logged in in any other blog in the network. Is it possible to do so?