I considered doing this for a current project, but having all the alarm messages permanently fixed made me reconsider. I'm using the ALMA and ALMD instructions, but not putting them in an AOI.
I'd like to be able to access the Message string in the UDT as well. It looks like everything else is accessible, just not the Alarm Message string. I have found a way to edit them outside the wizard using the Export Tags and Logic Comments and that is OK for offline work.