headers in reply message

[shaveht]

Hi there,
when i send a message in reply to another one, the message contain header:

UID 9014) References: <47FF1A18.1080404@............>

UID 9014) Message-ID: <9b413dee5adb9f027015a36b1cadbb3b@.............>
X-Sender: ..........
Received: from .................
with HTTP/1.1 (POST); Fri, 11 Apr 2008 16:12:53 +0200
User-Agent: RoundCube Webmail/0.1-rc2 Content-Type: text/plain;
charset="UTF-8" Content-Transfer-Encoding: 8bit

how i can remove this?

thanks