Anyway, I did this simple mod. I just removed top cover and drilled a 3/16" hole through it, near where the barometer sensor is.
NOTE 2015-06 : Ever since I did this mod, my Barometer seems to be "drifting" more (not holding, even while sitting on desk). Not sure if I'm just paying more attention to an existing problem, or if it actually caused the problem. In flight, my Altitude-Hold Mode also drifts or holds poorly. At this time, I would not recommend this mod. I put some packing tape over new hole to block 80% of opening. It's back to normal now. It works better outside than inside, but that's ok.