Databinding. New record. How to modify a value

[LEM]

Hi,

I'm very new with databindings and I'm trying to insert a new record in
a table.
Just by dragging and drop I don't have to add any code, because
everything is done automatically. The save function that is created is
this one:

private void c03BindingNavigatorSaveItem_Click(object
sender,EventArgs e)
{
this.Validate();
this.c03BindingSource.EndEdit();
this.c03TableAdapter.Update(this.aSAMDataSet.C03);

}

The problem is I get an error 'Column 'ID' does not allow nulls'
because I need to populate that column with a value. That's what I
don't know how to do. How can I access to that column?

Could anybody help me with this?

Thanks a lot.