Thanks for your answer. I've tried this yesterday evening. The setup went out with an error and unity never came back (error from MALEx_MC, I've found afterwards described in this tech note : "Cisco Unity 3.x: AvCsMgr Service Does Not Start After Running Configuration Setup" : http://www.cisco.com/warp/customer/788/AVVID/mailstore-no-start.html).
Hopefully I've been able to restart the server in its previous configuration since I had kept one RAID disk out.
I'll try to understand and then follow the steps described in this tech note. I'll come back to you if I still cannot sort this out.
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.