Hi raywil77,
You can save this in a Registration, so you can then load this MP3 later via this Registration. Please note, however, that later MP3s loaded normally (directly) will also be pitch-changed as long as you do not set the audio pitch back to zero.
I recommend making the desired pitch change for MP3s using a suitable computer program, then you can later play them normally on the Genos.
Best regards,
Chris