Accoording to the manual 'parallels Plesk Panel 10' (no date and/or version available), side 172, email notifications can contain placeholders which should replaced with some vars.

Problem here (Plesk 10.3): <user_contact_name> and <user_login> is NOT replaced.
Furthermore the email looks currently ike this (customized):

Hello <user_contact_name>,

we have created successfully your new account.

Below are your access data which shall not be shared with others (see TOC).
Additionally we recommend to change your password after the first login.

Username: <user_login>
The manual is not right here, instead of

user_contact_name
which should be

client_contact_name
and

user_login
should be

client_login
Maybe this helps others - the manual should be corrected!