To have autoresponders in HSPC you will need to log into your HSPC control panel and go to System Tab > Applications > Add Application. Install the HSPC application Majordomo with Autoresponder.
Once Majordomo with autoresponder has been fully installed you will be able to see the autoresponder feature for each mailbox at System tab > Mail Management > Mailboxes. Click on a Mailbox then configure your autoresponder options. Click on the Save button to save these options.