If I understand correctly, you want to fill the form once, and use the data later or more then once in the scripts?
I dont know how it would be done with an HTTP header.. I have done it by either simply writing the data to a .TXT file and rereading it as necessary... or by using sessions and registering the variables... then all you have to do is open the session and you again have access to these variables....
Hope it helps... hope I answered the right question....?! 🙂