Updated on 27th Jan'12
In SEP 12.1 save username & password option is not enable by default.
This feature is only applicable in Enterprise Edition, it's not applicable in Small Business Edition.
Default login screen is as below.
You have only option to click on forgot your password
logon to SEPM --> Click on Admin --> Click on domain --> Select Default --> Edit domain properties --> Select Password tab --> Select allow uses to save credentials when logging in
You can set logon banner also.