[Exim] Using cyrus-imapd for local deivery

Hi all after about a day reading various howto's and documentation Ive
set exim to use cyrus-imapd for local delivery using the following
syntax in the configure file:


local_delivery:
driver = pipe
command ="/usr/pkg/cyrus/bin/deliver -l"
return_path_add
return_output
prefix= ""
user = cyrus

i have created a user whilst logged into cyradm as cyrus called
user.brent and set a passwd for the user via saslpasswd

now everytime i try and send a mail to the user from the local machine
as root by using

sendmail brent

i get the following reply, it doesnt recognise brent as a local user:


001-11-13 12:02:16 163cGc-00004Z-00 <= root@???
U=root P=local S=361 2001-11-13 12:02:16 163cGc-00004Z-00 **
brent@???: unknown local-part "brent" in domain
"webscreen-technology.com" 2001-11-13 12:02:16 163cGe-00004b-00 <= <>
R=163cGc-00004Z-00 U=root P=local S=1280 2001-11-13 12:02:16
163cGc-00004Z-00 Error message sent to root@???
2001-11-13 12:02:16 163cGc-00004Z-00 Completed


What am i doing wrong?? Has anyone seen this before?
--
Cheers

Brent