[CentOS] syslog-ng 2.1.4 - file sources are read only when reload or restart is performed?

Hi All ;)

I am using a virtual machine with:
Red Hat Enterprise Linux Server release 5.7 (Tikanga)
Linux logserver01 2.6.18-274.el5 #1 SMP Fri Jul 8 17:36:59 EDT 2011 x86_64
x86_64 x86_64 GNU/Linux
syslog-ng 2.1.4

I have following configuration:

...
  9 options {
 10         create_dirs (yes);
 11         dir_group (root);
 12         dir_owner (root);
 13         dir_perm (0700);
 14         group (root);
 15         owner (root);
 16         perm (0600);
 17         flush_lines(1);
 18         flush_timeout (1000);
 19         keep_hostname (yes);
 20         log_fifo_size (1);
 21         use_dns (no);
 22         use_fqdn (no);
 23 };
...
 39 source s_stdout {
 40 #       file ("/logs/stdout.log" flags(no-parse) follow_freq(1));
 41         file ("/logs/stdout.log" flags(no-parse));
 42 };
...
61 destination d_stdout         { file("/var/log/$YEAR$MONTH$DAY/stdout");
};
...
80 log { source(s_stdout); destination(d_stdout); };

The problem is that changes in /logs/stdout.log are only visible in
/var/log/20140717/stdout when I perform /etc/init.d/syslog-ng reload or
restart. I tried several settings of flush_*, log_fifo_size and follow_freq
but with no luck :D

Is it a problem withe the version that I use (quite old :D ) or is there a
mistake in my configuration maybe?

BR,
Rafal.