If you are a Create Hosting customer, you will be able to utilise the Automatic Updater if you installed Wordpress via Application Vault from within Parallels Plesk Panel. If you installed Wordpress manually, you will find that the Automatic Updater only supports FTP as default. Do not fear however, as there is a handy plugin at http://wordpress.org/extend/plugins/ssh-sftp-updater-support/installation/ that provides SSH SFTP Updater Support. You should be able to search for and install this directly from within Wordpress (go to Plugins > New).
//define ('FS_METHOD', 'direct'); define('FS_METHOD', 'ssh2' );You should then be able to upgrade directly from within Wordpress. When you perform the upgrade for the first time, you will be prompted for your SSH/SFTP access details. Select SSH2 as the protocol, and enter your SSH/SFTP access details as provided in your account settings email. Be sure to enter the port number (as provided in the account settings email) after the hostname (e.g. example.co.nz:22)
If you are a Create Hosting customer and having difficulty with this, drop us a support ticket and we'll help you out.