Outlook 2003 email properties

In Outlook 2003 I want a right click menu item on an email to add keywords, say max 50 characters. These keywords should show up in the overview. See the attached jpg. When choosing the menu item 'keywords' I want a textbox to fill in some text. When I choose an emailitem that already has keywords I want to see them so I can modify them. Should be written in C#/VS2005/8. If a menu item is not possible I will settle for a button in the toolbar. The email items will be in the public folders section of Outlook. Concerns Microsoft Office Outlook 2003 SP3 Project includes a description of installation of the software in Outlook and making necessary alterations to the layout (i.e. the keywords column in the overview).