It will sort of work, the problem is the power off. I believe the harmony remote sends a macro to do the power off, not the BT adapter itself.
I have one of these also and I am thinking of dumping it on ebay and getting this instead:

http://www.ps3toothfairy.com/

They even have a DIY version where you pull the BT module out of the official PS3 blue tooth remote for 40 bucks.