VSTO and Outlook 2003 shortcut menus

I want to have Outlook 2003/2007 integration with my application using VSTO. Outlook 2007 is fine - I have all the hooks I need, but with Outlook 2007 I can't seem to find how to add a context menu item to mail items in my Inbox. I have not found an event handler to populate the context menu like the 2007 version.

Do you know a workaround?