There was a discussion of seeking into MP3s and why it doesn't work (isn't supported) here: viewtopic.php?f=34&t=30673&p=233555
Thanks for posting the link. Even if seeking isn't supported in roAudioPlayer there are still a few features that could be added to improve the audio support. I think a playback notification event should be a priority. The springboard screens currently provide a progress indicator if the content type is set to "audio" but there's no way to retrieve the current playback position making it rather pointless to display a progress indicator.