[Exim] change users spool directory

My problem: I'm running my fetchmail on SuSE as well as on
Debian Sarge. So I would like to set a new user's spool
directory. Setting the value "spool_directory = /suse/var/spool/mail"
in the /etc/exim4/configure + dpkg-reconfigure exim4-config
doesn't work because the incoming mail still is put into
/var/spool/mail/<user>.

Any way to change that (I had no success with spec.html) ?

Thanks!

Hermann Flacke