As per the example you mentioned, on extension 403, i press superkey, say yes to login, enter ACD Agent ID 404(Let's say i gave ADC agent ID as 404), the display asks for password and gave password. Now the display say's connecting and after 5-6 seconds, the display say's logged out.
Some more background:
I am using Mivoice Business 7.0 PR1 version
Please find the attached document