This is a  tutorial/howto on adding a subdomain with IspCP

Login to your IspCP control panel as a client

1) Click on “Manage domains” on the top panel

2) Click on add subdomain

* Subdomain name :: Give the subdomain name
* Directory tree mount point :: by default it will be same as subdomain name, you can change it if you want to point the subdomain to another dir

Click on add button at the bottom to add the subdomain

3) Add a redirect / Forwarder for a subdomain

* Subdomain name :: Give the subdomain name
* Enable Forward :: enable it
* Forward to URL :: give the url to which you want to forward the subdomain

Click on add button at the bottom to add the subdomain and create the redirect.