jEmplode 37 is much smarter about this. One of the problems is that jEmplode doesn't care about non-MP3 files (for transport purposes like you said). However, it doesn't currently set a codec on the files (since there isn't a codec for a .txt file). The problem with that is that currently not having a codec is one of the triggers for Emplode to "upgrade" the tune from the 1.0 series. So it appears that Emplode goes through and sets the codec to be "mp3". I'm going to try setting to codec to something bogus to see if Emplode will ignore it...
Maybe the Empeg guys and I can agree on a standard "magic" codec that can be used for taxiing files.
As part of all this, 37 fixes that downloading problem too (i.e. wrong extension attached).
Mike