Make Store Type Private Property [Outlook 2003 API Reference]
Treats a secondary store as private.
A store provider can use this property to have Outlook treat it as private when it is a secondary store for a user.
By default, Outlook treats a secondary store the same way as a delegate store, and items in the secondary store are private only if the user marks them specifically as private. When this property is true, items deleted from a secondary store are moved to the Deleted Items folder in the primary store. Items marked private are not displayed. Drafts are stored in the Drafts folder in the primary store.
This property is ignored if the version of Outlook is earlier than Microsoft Office Outlook 2003 Service Pack 1, or if its value is false.