That's one reason I dislike wamp3... You can't configure anything, at least not where you'd expect to find configuration options.
In wamp2.x it was very easy to change the way files were displayed in the browser, wamp3 resembles of MS wizard
I'm sorry I have no insight on this, I still use 2.8 (though I do have 3 installed on one computer, just for experiment)
-M