Apache aliases

Hi ,
I tried to change some alias in Apache server.
Trying to make aliases to open http://www.domainame.com/webmail mail.domainname.com.

Quote from gOOvER

mail.domain.com is used for eMail itself.

You can add webmail.domain.com

OK. But when I type in the Adress bar mail.domain.com I`ts opened the admin login panel not webmail login clients

In settings where the section Ip management have to add two more IP address
***.***.***.** mail.domain.org nickname изтриете IP
***.***.***.** http://www.mysite.info nickname eth0 изтриете IP
***.***.***.** hostingdomainname.com nickname eth0 Protected
And I add the user who uses the IP-which is set to hostigdomainname.com and ask dns reverse lookup show me the ip address ho i use mail.domain.org
Why do you think is it?