[torqueusers] submiting with -u option

[Arnau Bria]

Hi all,

some student in our center is doing a torque web interface for
submitting jobs.
His real user is apache, and he's trying to use -u qsub's option for
modifying his id.

But he gets an error like:
$ echo sleep 0|qsub -u neuro -q test
qsub: Bad UID for job execution MSG=ruserok failed validating arnaubria/neuro from ui03.pic.es

(that's my example, his shows something like this but whit apache his
user).

So, anyone could explain me how to use and/or configure cliet/server
for beeing able to use -u option?

TIA,
Arnau