Hmm, link works fine for me. Here's another with some screens of damage:
http://www.livejournal.com/users/faranim/34378.html (scroll down for pics)
The triple damage kicks in like triple attack, only with ranged attacks and the damage is identical. So you shoot 1 arrow for 130 points of damage, and your log reads that you shot 3 arrows for 130 points of damage each. They're claiming a 5-10% activation rate, though they haven't noticed it activating with Namas Arrow. There's also a pic demonstrating Namas Arrow's ability to create a light SC off of a light SC.