Quote from Degenerate
Hmm, well my understanding is that you cannot setcookie or do header(Set-Cookie: ) for a domain other than the one your script is hosted on in php?
Set-Cookie is used by the server to send a cookie to your browser. In this case you need to send a cookie to the server. This is done using the Cookie:-header. In that case you don't need to specify a domain. How you implement this depends on the programming language you use. If you use PHP/curl, you can probably do something like
curl_setopt($ch, CURLOPT_COOKIE, "PHPSESSID=...");
(Note that the documentation on CURLOP_COOKIE at php.net talks about "Set-Cookie:", which is an error or just confusing)
A good way to see how Set-Cookie and Cookie work is propably to install livehttpheaders
plugin for firefox and look at the output.