UI_METHOD functions not being invoked for smart card

[George]

Hi,

    I'm trying to get OpenSSL 1.0.2u with the FIPS Object Module 
2.0.16  in Windows 10 to prompt the user for a smart card's PIN number 
every time the application is launched. However, I cannot seem to get it 
to work. My UI_METHOD callback functions are not being invoked.

I'm using the following code as a reference:
https://github.com/jjkeijser/ppp/blob/eap-tls/pppd/eap-tls.c

I tried the following:

   UI_METHOD* transfer_pin = UI_create_method("transfer_pin");

   int writer (UI *ui, UI_STRING *uis)
   {
        PW_CB_DATA* cb_data = (PW_CB_DATA*)UI_get0_user_data(ui);
        UI_set_result(ui, uis, cb_data->password);
        return 1;
   };
   int stub (UI* ui) {return 1;};
   int stub_reader (UI *ui, UI_STRING *uis) {return 1;};

   UI_method_set_writer(transfer_pin,  writer);
   UI_method_set_opener(transfer_pin,  stub);
   UI_method_set_closer(transfer_pin,  stub);
   UI_method_set_flusher(transfer_pin, stub);
   UI_method_set_reader(transfer_pin,  stub_reader);

   pkey = ENGINE_load_private_key(pkey_engine, pkey_identifier,
   transfer_pin, &cb_data);



However, none of the callback functions "writer", "stub", or 
"stub_reader" actually get called. Do I need to do anything else to 
enable this functionality?  I would like to force the user to enter PIN 
number every time.



Thanks,
George