I'm not clear about where you're trying to redirect to.
You can add the subdomain in Panel:
[color=#00CC00]Domains > Manage Domains >[/color] [color=#0000CC]Add New Domain / Sub-Domain[/color]
Redirection to a domain can be accomplished on the next page. If you want to redirect to a certain page within an existing domain, the best thing to do is setup redirection rules in the new subdomain's .htaccess file.
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