Motorola E815 / E816 Hollywood

I bought a Jabra C120s stereo headset last week to use with the e815 for listening to mp3s. The sound quality is great, but it's way too loud. I did the "set audio level" opcode mod, but this doesn't appear to change the volume range for an attached headset (via the 2.5mm connector). I have a choice of silent (at the lowest sound setting) to really loud at the next higher volume setting.
Any suggestions are most appreciated.