Tienes que hacerlo tú.
Priemro descargas la 7 y actualizas, luego abres un ticket para que te cambien la licencia.
QUOTE
This option is for the license key for 7.0 only; the installation or upgrade of Plesk will not be performed by EV1Servers. We will require root access to your server to perform the key installation. If you do not have Plesk 7.0 installed on your server, the installation of this key will disable access to the Plesk GUI until you perform the upgrade. Plesk must be installed on the server before we can perform the key installation. This upgrade is provided free of charge to our existing Plesk 5.0 or 6.0 customers; however, those who did not previously possess a Plesk server will be assessed a one time $49.00 processing fee.