No you don't =) You want /home/jim/jim.xxxxxxx.com to be the 'Web Directory'.
If the subdomain already exists, then go to Domains -> Web and 'Edit' the subdomain so that it is 'Fully hosted' and set the 'Web Directory' to /home/jim/jim.xxxxxxx.com
If you are goign to create the subdomain, make sure you select 'Fully Hosted' and specify the 'Web Directory' as above. Then login as jim if necessary to upload the web site files into the jim.xxxxxxx.com directory.
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