Using the ScheduleDefinition.GetSchedulableFields it is possible to iterate through the available (shared) parameters and add or insert (addfield or insertfield) them to the created schedule.
However I wish to add a calculated value / calculated field to the schedule. This field does not show up in GetSchedulableFields because this field has to be added 'on the fly'. In the API there is a schedulefieldtype.formula member which suggest it may be possible to add a calculated field. Do you know how to add a calculated field because I am running out of ideas. Or is this not possible (yet)?