Deny write-permission on a folder in my own Mailbox

[MarioFromBelgium]

Hi,

WIN XP PRO UK SP2, OUTLOOK 2003 SP2
WIN 2003 R2, EXCHANGE 2003 SP2

I need to deny myself write-permission on a folder in my own mailbox. Actually
it is an addon that keeps writing to a folder while it shoudn't.
I have set sharingpermissions to this folder as followed :

default : none
anonymous : none
myself : reviewer

That doesn't seem to work?
Any ideas!

Mario