PortMIDI interface

I have got MuseScore 0.9.6.3 and Windows XP 3rd.
Last week I bought a Keyrig 49 with M-Audio Series II MIDI -- Windows Drivers Version 4.2.03.
My aim was both to play and also enter notes i MuseScore, which I now don't understand how to do (I am not ver good in IT).
According to MuseScore Handbook, page 11 = " If you have multiple MIDI devices connected to your computer you may need to tell MuseScore which one is the MIDI keyboard. Using version 0.9.6 or
later go to Edit → Preferences... (Mac: MuseScore → Preferences...). In the
preferences dialog click on the I/O tab and select your device under the
section labeled "Choose PortMidi input device" .

BUT this field is empty and no option available , which leads to my question= How do I get "Keyrig 49 " in this field,
or is there another way to enter notes in MuseScore from my keyboard?