gtk combo box issues

[Allen <allen saucier cas-inc com>]

Hi all,

I am trying to build a combo box's content on the fly but I'm missing 
something & I don't know what it is.  Would someone please help me? I am 
able to add a Row to the Combo Box.  I am able to set the value of that 
row.  But the value does NOT  APPEAR  when I click the combo box down 
arrow button.  Just a BLANK  ROW  appears.   Here is the code that I'm 
using:

In the HEADER:

  class CFireButtonMortarTrajModelColumns : public 
Gtk::TreeModel::ColumnRecord
  {
    public:
      CFireButtonMortarTrajModelColumns()
      {
        //add(m_colRowNumber);                     // position 0
        add(m_colFireButtonToMortarTrajLineName);
      }; ///< ctor
            ~CFireButtonMortarTrajModelColumns() {;}; ///< dtor
        public:
          Gtk::TreeModelColumn<int>  m_colRowNumber; ///< Row Number
          Gtk::TreeModelColumn<int>  m_colFireButtonToMortarTrajLineName;
  }; // class CFireButtonMortarTrajModelColumns

Gtk::ComboBox    *m_comboboxFireMortar1TrajName;
CFireButtonMortarTrajModelColumns  m_cFireButtonMortarTrajModelColumns;
Glib::RefPtr<Gtk::ListStore> 
m_glsFireButton1MortarTrajConnectionComboBoxList;


IN the CPP:

m_refGlade->get_widget("combobox_fireMortar1TrajName", 
m_comboboxFireMortar1TrajName);
m_glsFireButton1MortarTrajConnectionComboBoxList = 
Gtk::ListStore::create( m_cFireButtonMortarTrajModelColumns );
m_comboboxFireMortar1TrajName->set_model(m_glsFireButton1MortarTrajConnectionComboBoxList); 

 
m_glsFireButton1MortarTrajConnectionComboBoxList->append()->set_value(m_cFireButtonMortarTrajModelColumns.m_colFireButtonToMortarTrajLineName, 
p_iTrajectoryLineNumberToAdd);

This code produces a BLANK  ROW  in my combo box.  What am I not doing 
that is preventing me from seeing the value displayed?

Thanks everyone.  I really appreciate your help.

--Allen