How to configure permissions of log files created by rsyslog

Issue

• How can the default permissions of a log file (e.g. /var/log/messages) be changed to make it world-readable or world-writeable?
• Changing permissions of system log files via create directives in /etc/logrotate.d/syslog doesn't work with rsyslog v5 (e.g. in RHEL6). No matter what is configured via logrotate, log files always have 600 permissions.
• Using rsyslog options $umask and $FileCreateMode does not update my log permissions.