I know what you mean about the silent shifts. I set up my girlfriend's RB-2 with campy 9 shifters, hub-bubbed Shimano derailleur, and 8 speed shimano cassette and those shifts can happen without any audible feedback. Funny how you sometimes don't notice the difference until you get visual/audio feeedback.
How are you liking the Shimergo combo? I think it provides a very smooth system. Shimano cassetes FTW.