c# 2005 add_In Excel 2003

[C# Programming]

Salam

with Add-in installation and setup information
to automatise Excel ,I can't create new NamedRange
in methode public void OnConnection(object application, Extensibility.ext_ConnectMode connectMode, object addInInst, ref System.Array custom)

or to cast Microsoft.Office.Interop.Excel.WorkSheet to
Microsoft.Office.Tools.Excel.WorkSheet

Thanks http://www.barakasoft.com/script/Forums/Images/smiley_doh.gif

good day for all