I haven't tried that exact situation personally, but I was wondering if you are using software or hardware-based conferencing? Also, so I understand that when you call to the IP phone from the VG200 (i.e. outside) and then you press conference and dial out, or is it when you have two outside callers on the same phone and you try to conference? If it's the latter case, do you have both calls on the same line appearance?
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.