Hello,
I'm having a similar problem too. When modifying the script on "GUI Text and Messages" ASA section, and typying the message I want in the msgstr"" field, it is not working. I know it is necessary to reconnect anyconnect to view the final changes, but still not seeing anything related to the messages I've modified. I'm testing this with the Login Failed message without sucess. I don't know if anyone knows how to make it work.
I'm doing this with Anyconnect 4.9.01095 and I could realized that the script says "Project-Id-Version: AnyConnect 4.7.00000\n" , I don't know if that could be the reason I'm not getting the message I want.
Thank you in advance.