Just add the port onto the same MGCP GW in CUCM, determine which slot the port is located in by using "sh diag", then in CUCM configuration go to the GW and add that port as MGCP FXS port, you will then be able to assign a DN to it just like a phone.
Correct, you should not need to do anything on the actual GW with MGCP as all config gets downloaded from CUCM. I don't have a recent example, as I stopped doing MGCP 5 years ago due to numerous issues I encountered with it over the years, I switched to H323 and recently to SIP.
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.