.WAV files for sound pads? (Pod Trak P4)

[BruceGlover]

I'm trying to put a song on the SoundPad C. I drag (using my macbook Pro) an mp3 to the pod trak sd card. it shows up on the podtrak screen under "files" . When I try to assign it to sound pad C it says "invalid file".  Earlier today I did the same thing with another file and the Pod trak converted the mp3 to .WAV. (and of course I could place it on the sound pad. ) How can I do the same thing again?

[BruceG1]

Actually, I got a new SD card and updated the firmware and now it seems to work, but still it's sporadic.  Sometimes I get the "convert to WAV" option and sometimes not. (I'm importing mp3s) I wonder if somewhere there's a definitive description of how this works????