Help! Add subdomain to folder

[huuloc]

Hello all,
I'm a newbie, first time I installed VestaCP on my VPS.
Normaly, I can add subdomain (vhost) on admin page (port 8083). But, I want add subdomain to folder.
Example: subdomain.mydomain.com ==> path "/home/admin/web/mydomain.com/public_html"
NOT "/home/admin/web/subdomain.mydomain.com/public_html"
Picture below :
http://imgur.com/1NDzFYd

Sorry, My english aren't well.

[SS88]

Edit the domain mydomain.com and set Aliases to include the subdomain.