Hi Elizabeth,
Im nearly sure you cant ,as this would require extra memory the Kn7000 dosent have.
The way I do it is to use Technics Audio Recorder software.It connects your keyboard to a computer which records everything that comes out your keyboard outputs.
Only drawback is the finished song is in your computer, not your keyboard.
But you could then transfer the audio file to your SD card.
Hope this helps.

Cheers Barry