[exim] Debian and exim - running through sudo

Hi There,

I'm testing exim on debian wheezy with Mailscanner and baruwa. Baruwa needs
access to run as the Debian-exim user so I have a sudoers file as follows:

snip --->
Defaults:baruwa !requiretty, visiblepw

baruwa ALL=(Debian-exim) NOPASSWD: /usr/sbin/exim4 -C
/etc/exim4.out/exim4.conf.template -M *, \
        /usr/sbin/exim4 -C /etc/exim4.out/exim4.conf.template -Mf *, \
        /usr/sbin/exim4 -C /etc/exim4.out/exim4.conf.template -Mrm *, \
        /usr/sbin/exim4 -C /etc/exim4.out/exim4.conf.template -Mg *, \
        /usr/sbin/exim4 -C /etc/exim4.out/exim4.conf.template -Mar *, \
        /usr/sbin/exim4 -C /etc/exim4.out/exim4.conf.template -qff, \
                /usr/sbin/exim4 -Mrm *, \
                /usr/sbin/exim4 -Mg *, \
                /usr/sbin/exim4 -Mar *

baruwa ALL = NOPASSWD: /bin/kill -s HUP *
<---snip

If I run the -qff command I get the following;

2013-05-20 11:51:31 Couldn't chown message log
/var/spool/exim4.out/msglog//1UeN07-0006cv-7h: Operation not permitted

Can someone point me in the right direction on this? Why can't I run queue
commands through sudo as another user?

Thanks for any response.

Cheers,
Mark