Saving Form Region Data in Outlook 2007

I am creating an Outlook 2007 add-in that adds a form region to an appointment that a Us开发者_高级运维er creates. What is the best way of storing & associating the data that the User inputs in my form to the appointment they have generated.

Where would you like to save it:

http://msdn.microsoft.com/en-us/library/microsoft.office.interop.outlook._appointmentitem_properties.aspx

?