i'm working on a mail script, and have problems with the mail-header.

mail header looks like this:

Envelope-to: coders@lungelunge.dk
Received: from nobody by kartoffel with local (Exim 3.12 #1 (Debian))
id 13M828-0001Ql-00
for <coders@lungelunge.dk>; Tue, 08 Aug 2000 13:59:00 +0200
To: coders@lungelunge.dk
Subject: New article added to the knowledgebase
From: ulrik@lungelunge.dk
Reply-To: ulrik@lungelunge.dk
X-sender: ulrik@lungelunge.dk
Message-Id: <E13M828-0001Ql-00@kartoffel>
Sender: nobody <nobody@lungelunge.dk>
Date: Tue, 08 Aug 2000 13:59:00 +0200

what i want to change is the;
"Sender: nobody <nobody@lungelunge.dk>"
to ex.:
"Sender: ulrik <ulrik@lungelunge.dk>"

how would i do this???

i tryed to put
"Sender: ulrik <ulrik@lungelunge.dk>"
into the header section of the mail script but without any luck