There is a known bug in the BeatBuddy firmware, and I wonder how far You have come in fixing this.
There is no way to adjust the volume for accent hit with MIDI.
From the manual:
“CC-110 [0-127] Triggers an accent hit with a volume from the value 0 (mute) to 100 (original recorded volume) to 127 (amplified more than the original recorded volume)”
When I send value 0 its muted, but value 1 to 127 is the same volume - no difference.