Sign the Self-signed certificate of cisco by 3ed party CA
You will run through a process of using Cisco Unified OS to generate CSRs for he 3rd party certs, then, its just a matter of utilizing the CAPF feature for the phones and uploading the 3rd party certs using the CTL client plugin. Here is a good detailed doc, describing the process and configuration steps:
Are you getting this error “Installer User Interface Mode Not Supported. The installer cannot run in this UI mode. To specify the interface mode, use the -i command-line option, followed by the UI mode identifier. The value UI mode identifiers...
The below trick might come handy when you have to add a new node to a cluster but you don't have or is unsure of the security password for the publisher. This procedure has been around for ages.
1) Login into the CLI of the Publisher.