Outlook: Deleting Cached Messages in IMAP Accounts

How can I delete cached messages from an IMAP account in Outlook 2002? I can't find any equivalent for Outlook Express's Remove Messages command to remove message bodies but leave the downloaded headers.

Outlook 2002 is the first version of Outlook that lets you mix Exchange Server and IMAP accounts, making it possible to access all the folders in Exchange Server mailboxes in different organizations. However, Outlook's implementation of IMAP is different from that in Outlook Express.

Outlook 2002 creates a Personal Folders (.pst) file for each IMAP account and caches both downloaded headers and message bodies in folders in that .pst file. The tools for managing messages are the same as in regular .pst files. I haven't been able to find any equivalent of the Remove Messages command in Outlook Express; apparently you can't remove cached message bodies in Outlook 2002 but keep the downloaded headers visible in the folder.