When you connect a Microsoft Windows SharePoint Services task list to Microsoft Office Outlook 2007 or Microsoft Outlook 2010, some columns may not appear in Outlook.
This issue may occur when the SharePoint task list includes custom columns. You can synchronize a limited set of predefined properties by using the Connect to Outlook feature. However, you cannot connect custom SharePoint task list columns to Outlook.
All Outlook users see the same information when they view synchronized SharePoint task list items. This is true even if an Outlook field such as Categories does not appear in Internet Explorer when you view a SharePoint task list. Outlook synchronizes these properties to other Outlook users through the server that is running Windows SharePoint Services.
To view an Outlook field such as Categories in Internet Explorer, add that field as a column template. To add an Outlook field to the SharePoint task list, use the Add Site Columns command on the Settings menu in the SharePoint task list. Administrators can use this feature to make the appearance of the synchronized SharePoint task list more consistent with Outlook and can sync a limited set of predefined properties.