Without the aaa authentication listener command, when HTTP(S) users need to authenticate with the security appliance after you configure the aaa authentication match or aaa authentication include command, the security appliance uses basic HTTP authentication. For HTTPS, the security appliance generates a custom login screen.
If you configure the aaa authentication listener command with the redirect keyword, the security appliance redirects all HTTP(S) authentication requests to web pages served by the security appliance.
http://www.cisco.com/en/US/docs/security/asa/asa72/command/reference/a1_72.html#wp1442790