[exim] $home in filter file, empty variable

Hi

This has been bugging me for days... I've got $local_part, $domain etc
etc, but the variable $home is missing, anyone got any idea why?

I'm calling the filter like this:

central_filter_test:
driver = redirect
directory_transport = address_file
file = /etc/exim/centralfiltertest.exim
no_check_local_user
no_verify
user = root
allow_filter
allow_fail

All I got in the filter file is this

# Exim filter

logfile /var/log/debug.log

logwrite "$tod_log home=$home mi=$message_id domain=$original_domain
localpart=$local_part ip=$sender_host_address sender=$sender_address
header_from=$header_from: subject=$header_subject"

it's all there except the value of $home, anyone got an idea?

Rgds, team mail