VBR rules! Yes, you should encode with at as opposed to average bitrate. I wouldn't think that real player would have any problems playing it. Real Player should see it as just an .mp3 file encoded @ XXX kilobits per second. VBR is the algorithm applied to the audio stream during encoding..... It has huge advantages over ABR. It definately produces smaller files at better quality!
BTW... ever check out Ogg Vorbis?
ls