Can SmarterMail (when using Exchange Active Sync), make use of the icon in Outlook labeled "Follow Up"? Exchange users and POP3 users are used to being able to specify a date when they want to follow up. (i.e. Follow Up -> Today, Tomorrow, This Week, Next Week, No Date, Custom).
Follow up options with MS Exchange or POP3 accounts
Follow Up options with SmarterMail EAS or IMAP: