Since the Flash Player (or, more exactly, the URLLoader class) will not let you read HTTP response headers or cookies set by the server, and if you get hold of a session cookie
Some of your post may have eluded me, but do you know about Shared Objects:
"The SharedObject class is used to read and store limited amounts of data on a user's computer or on a server. Shared objects offer real-time data sharing between multiple client SWF files and objects that are persistent on the local computer or remote server. Local shared objects are similar to browser cookies and remote shared objects are similar to real-time data transfer devices.