On the server side you can access the cookie via $_COOKIE['cookie_name'].
Also remember that since HTTP is a stateless protocol, you have to send the cookie with every single SOAP call in order for it to be visible at server site.
It seems obvious but might save one a lot of time.
SoapClient->__setCookie
lukasz at szostak dot biz
14-Aug-2006 10:53
14-Aug-2006 10:53
