Parameters are accessed with C4DAtom::GetParameter()/ C4DAtom::SetParameter(). See Parameter IDs.
Parameter: Note
TODOWORLD_TASK_NOTE
Parameter: Move Selected Items to Done
TODOWORLD_DONE
Parameter: Delete
TODOWORLD_TASK_DELETE
Parameter: Note
TODOWORLD_DONE_NOTE
Parameter: Move Selected Items to Task
TODOWORLD_TASK
Parameter: Delete
TODOWORLD_DONE_DELETE