Hello Dave,
Outlook's Junk folder is their definition of the Spam folder. If you are trying to access the Spam folder that is used by SpamAssassin on an InMotion hosting account, then you would need to subscribe to that folder. Note that the link I'm placing in this reply says it's for Outlook 2010, but it's basically the same process. Note that in order to subscribe to a folder however, you would need to be using IMAP as your email protocol. If you're setup with POP3, then you cannot subscribe to the folder.
You can always access your SPAM folder (if it's enabled in SpamAssassin) using webmail.
If you have any further questions, please contact technical support available 24 hours a day / 7 days a week.
Arnel C.
InMotion Hosting
Community Support Team