Model - data

Hi I created a model...
I need to add 2 more columns to it. One for "name" and one for "comments".
What should I return in a "data" function of the TableModel since these 2 columns wont be stored in "data storage" of the model where the actual model data are stored ?
THese 2 columns are just for the user orientation in a View...

By default models return QVariant() (i.e. invalid variant object) if they don't have the value they should return.