Can't post a form to a different subdomain via Ajax (WARNING: Can't verify CSRF token authenticity)

Question

I trying to send a remote form to a different subdomain (example.domain.com) from the one of the form (domain.com), but i keep getting the warn WARNING: Can't verify CSRF token authenticity in the log, and inspector in chrome tells me that the status of the request is (canceled), with the type application/x-www-form-urlencoded.

This is the form: button_to "Follow", follow_users_url(subdomain: post.user_username_slug), remote: true

When i remove the remote: true, i got the result i was hopping for. Also, when a try to use the same form in the same subdomain of the action (example.domain.com), i got the correct result.

I found a way to share the cookies in all subdomains (domain: :all in session_store.rb), but i can't found a way to share the token in Ajax requests.

I'm using Rails 3.1.3, Ruby 1.9.3 and jQuery 1.7.1.

Anyone can help me, please?

Edit:

The problem seems to related to CORS. Now i'm trying to find a minimum friction solution to make this (Asynchronous) cross subdomains requests work.