[Nut-upsuser] upssched problem on NUT 2.4.3

[Dupdup Sys]

Hello,
I am currently building a new server using debian amd64. Therefore I 
need to use my UPS EATON Evolution 1550 on it, using usbhid-ups driver.
I installed nut with apt (version 2.4.3-1.1squeeze1) on debian 2.6.32-5 
amd64.

I can currently use nut with the drivers, upsc and upsmon: my UPS is 
detected and works. Actually everything works except upssched: I can 
shut down the server using upsmon -c fsd. I didn't try yet but I think 
the automatic shutdown  would work either, the server should stop when 
the ups battery goes too low.

However I definetely can't make upssched running, which is such a big 
deal because I would like to use the timer functions to have a shutdown 
after ten minutes without electricity.
I created in /var/run/nut an upssched folder to contain the upssched 
files, made chgrp nut.nut and chmod 755. My upsmon.conf contains the 
NOTIFYCMD /sbin/upssched.

Here comes the issue: I can't find any lead of upssched in 
/var/log/daemon.log. While usbhid-ups, upsd and upsmon have their 
entries in the logfile and are working, I can't find anything about 
upssched in the logs. Thereby I do think that upssched is inactive, but 
I am still wondering if the problem is not in upsmon: I tried several 
permissions, tried to use an other script in upsmon.conf, but didn't 
manage to have it working.

Do you have any idea on how this could be solve ?
Best Regards.