mp3 sound alert on c330

I have a c330 and I'm trying to get it to alert me of Rest Areas on my route. I downloaded a rest area .csv file and a rest area .mp3 file. Example: Rest Area.mp3 and Rest Area.csv but when approaching a rest area, the mp3 does not play. I can get a proximity alert when using Manual mode in POI loader and setting a distance, but I can not get an mp3 alert. Does the c330 support mp3 playback?

Thank You!