http://lewiscarr.co.uk/2013/07/moodle-mysql-replication-phpmyadmin/

The phpMyAdmin that is bundled with cPanel doesn’t include user management so the following commands needed to be run to give the replication user the correct permissions:

Setting up the Master , add the slave replication user. The IP below is the slave IP.

mysql -e “GRANT REPLICATION CLIENT ON *.* TO ‘user_replicate’@’216.xx.xxx.xxx’;”
mysql -e “GRANT REPLICATION SLAVE ON *.* TO ‘user_replicate’@’216.xx.xxx.xxx’;
mysql -e “FLUSH PRIVILEGES;”

You should now be able to add the user user_replicate under Replication in phpMyAdmin.