Postgresql logging_collector = off ignored ?

Hello all.
I have installed postgreslq 8.3 on Ubuntu linux.
My postgresql.conf file is:
data_directory = '/home/postgres/8.3/main' # use data in
another directory
hba_file = '/etc/postgresql/8.3/main/pg_hba.conf' # host-based
authentication file
ident_file = '/etc/postgresql/8.3/main/pg_ident.conf' # ident
configuration file
external_pid_file = '/var/run/postgresql/8.3-main.pid' # write an
extra PID file
max_connections = 140 # (change requires restart)
shared_buffers = 128MB # min 128kB or max_connections*16kB
maintenance_work_mem = 512MB # min 1MB
max_fsm_pages = 1500000 # min max_fsm_relations*16, 6 bytes
each
max_fsm_relations = 2000 # min 100, ~70 bytes each
checkpoint_segments = 30 # in logfile segments, min 1, 16MB
each
log_destination = 'stderr' # Valid values are combinations of
logging_collector = off # Enable capturing of stderr and csvlog
log_rotation_size = 1GB # Automatic rotation of logfiles will
log_connections = on
log_min_error_statement = PANIC
log_line_prefix = '%m %p %u %d %r ' # special values:
log_lock_waits = on # log lock waits >= deadlock_timeout
log_statement = 'ddl' # none, ddl, mod, all
log_temp_files = 4096 # log temporary files equal or
larger
autovacuum = on # Enable autovacuum subprocess? 'on'
autovacuum_max_workers = 1 # max number of autovacuum
subprocesses
autovacuum_freeze_max_age = 2000000000 # maximum XID age before forced
vacuum
lc_messages = 'en_US.utf8' # locale for system error
message
lc_monetary = 'en_US.utf8' # locale for monetary
formatting
lc_numeric = 'en_US.utf8' # locale for number
formatting
lc_time = 'en_US.utf8' # locale for time formatting
deadlock_timeout = 1s

And I expect postgres not to produce any logs.
Unfortunately I keep getting new logs in
/var/log/postgresql/postgresql-8.3-main.log.
First of all I expected logs to be written in PGDATA/pg_log directory.
How can I redirect them to this location?
Secondly I want to be able to switch them off. What makes postgresql write
logs to /var/log/postgresql/postgresql-8.3-main.log when logging (I think)
is switched off?

Thanks in advance for help.
Ludwik

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Ludwik Dyląg