I've just installed ZCS 4.0.0 under SUSE Linux 10.1
I tried to change the admin login name "admin@..." to something different, but found I couldn't log in to the administration console. When I used "zmprov" to get a list of the users, I found that the original admin name "admin@..." was there, not the one I specified during the installation.
I was still unable to login, until I used "zmprov" to set the password of the "admin@..." user. It seems that the password I entered was ignored at well.
I just wanted to mention this as a "gotcha".