[Hampshire] kmail and cron

I am trying to get kmail to start using cron I did this earlier in the year,
then stopped using it and never made any notes of what the command I used was

Basicly I stop kmail running in the wee hours using cron (my pc runs 24\7) and
then I want cron to restart kmail. Here is what I have in cron at the moment

mit@Titan:~$ crontab -l
<snipped for clarity>
# start kmail
15 5 * * * /usr/bin/kmail --check

On the /usr/bin/kmail --check line I have used the following

kmail
"kmail"
'kmail'
/usr/bin/kmail
kmail -caption "%c" %i %m (this is the command from the start menu kmail icon)

But nothing seems to happen, certainly kmail does not start, cron logs report
that it ran or at least attempted to but does not give any further information.

If I open Konsole and type kmail then th e-mail client will launch.

Anybody help??

Tim