[Keeping the session after the redirect]

I've got a weird problem which affects only Safari browsers.

Site A offers user a login page and validates the credentials by calling HTTPRequest on site B ( this call starts new session, user password is checked and session id stored in the db).

If user login details are OK, site A redirects user to site B ( different domains and physical boxes).

 

It worked well before the last Safari update (5.0.1) - when user login is being checked, server B creates session X, after the redirect, session_start() creates absolutely different session Y.

 

All sessions are maintained by cookies only (SSL).

 

 

Any ideas how to maintain the same session during the redirect?

 

Thanks!