[CentOS] MySQL 5.1.69 at CentOS 6.4 doesn't know enable-named-pipe?

Hello,

I've only had experience with PostgreSQL sofar,
but have now to install MySQL (and WordPress)
on a CentOS 6.4 /64 bit server.

I have installed the mysql-5.1.69-1.el6_4.x86_64
package and executed the following commands:

# chkconfig mysqld on
# service mysqld start
# /usr/bin/mysqladmin -u root password 'xxxxx'
# /usr/bin/mysql_secure_installation

Then I've noticed that mysqld_safe process
is listening at 0.0.0.0 and decided to change that -
so that my WordPress installation only uses
domain sockets (or unix pipes? not sure).

So I've modified the /etc/my.cnf to:

[mysqld]
datadir=/var/lib/mysql
socket=/var/lib/mysql/mysql.sock
user=mysql
# Disabling symbolic-links is recommended to prevent assorted security risks
symbolic-links=0
bind-address = localhost
skip-networking
enable-named-pipe

[mysqld_safe]
log-error=/var/log/mysqld.log
pid-file=/var/run/mysqld/mysqld.pid

But now MySQL refuses to start:

# service mysqld restart
Stopping mysqld:                                           [  OK  ]
MySQL Daemon failed to start.
Starting mysqld:                                           [FAILED]

The  /var/log/mysqld.log contains:

 mysqld_safe Starting mysqld daemon with databases from /var/lib/mysql
  InnoDB: Initializing buffer pool, size = 8.0M
  InnoDB: Completed initialization of buffer pool
  InnoDB: Started; log sequence number 0 44233
 [ERROR] /usr/libexec/mysqld: unknown option '--enable-named-pipe'
 [ERROR] Aborting
  InnoDB: Starting shutdown...
  InnoDB: Shutdown completed; log sequence number 0 44233
 [Note] /usr/libexec/mysqld: Shutdown complete
 mysqld_safe mysqld from pid file /var/run/mysqld/mysqld.pid ended

I've searched Google and grepped
/usr/share/mysql/*.cnf for that directive,
but haven't found any hints there.

Any hints please?

Regards
Alex