Access list of digital certificates through builtin UI: (See related posts)

             X509Store store = new X509Store(StoreName.My, StoreLocation.CurrentUser);
            store.Open(OpenFlags.ReadOnly | OpenFlags.OpenExistingOnly);
            X509Certificate2Collection certs =
                X509Certificate2UI.SelectFromCollection(store.Certificates,
                    "Certificates", "Please select certificate to use", X509SelectionFlag.SingleSelection);