Displaying a history of direct mail campaigns

We have used the marketing campaign functionality for years to run our email marketing program.  One of the really nice features from a management perspective is that Sales Reps can easily click on the "Marketing" tab on a prospect record and see a complete history of email marketing templates that prospect has received.

We are now pushing out a new direct mail campaign and had assumed that if we setup marketing campaigns to represent those direct mail mailings, using the direct mail tab on the marketing campaign form, and assigning it the proper group of prospects, that these campaigns should also display int he list on the "Marketing" tab.  Unfortunately, that does not appear to be the case.