I've no idea what gyruby is, but I have never installed anything for the Fiire remote, just plug it in and the drivers install on their own ... done...
Never seen the volume issue, but then I don't use the "volume screen" I just use the volume up/down buttons on the fire remote - but note this is in digital/SPDIF mode, so LMCE isn't increasing/decreasing the volume on my sound card, it is sending the vol up/down RS232 messages to my amp. If you are using analogue sound and not controlling an amp, then LMCE is increasing/decreasing the volume on your sound card, which is completely different logic... so my experience would not apply to yours...