[Zope] Request-variable containing some user information

[Gitte Wange]

Hello,

I am trying to create a shop product to use with our payment gateway.
The gateway works in a very secure way and it's not easy to find out how it 
works.

I have some problems with the things that should happen after a users credit 
card has been accepted by the gateway.

You set an ok and a failure url in the gateway setup.
If the card is accepted, the gateway returns the page on the ok url. But it 
is the gateway that returns the url and therefor Zope think it's an anonymous 
user that is logged in.

Now is there some variable from the REQUEST object I can pass to the gateway 
in order to make Zope know that there is a user logged in ?
I have tried with HTTP_COOKIE but it didn't seem to work.

One other thing is that the form tag can only look like this:
<INPUT TYPE="hidden" NAME="sessionid" VALUE="<dtml-var 
"REQUEST['HTTP_COOKIE']">">

the sessionid variable is the only one the gateway doesn't strip :((

TIA,
Gitte Wange