A request XML packet installing an SSL certificate to Plesk certificate repository includes the install operation node:
<packet version="1.4.2.0">
<certificate>
<install>
¡
</install>
</certificate>
</packet>
The install node does not have a separate data type, it is nested within type CertificateActionRequest (certificate_input.xsd). The install has the following graphical representation:

Remarks
1. Certificate name must be unique in Plesk, meaning that two certificates with the same name cannot be installed, even if you want to install them to different repositories.
2. You can install only one certificate to only one repository within one install operation. Therefore, you must include either one domain node or admin node.
3. With one packet, you can install as many different certificates to any of the repositories as you want. To install multiple certificates, use the required number of install nodes in the packet:
<packet version="1.4.2.0">
<certificate>
<install>
¡
</install>
<install>
¡
</install>
¡
</certificate>
</packet>