Driving home, I thought about your problem a bit.
You fundamentally misconceive the structure of the issues and arguments, it's true, but your muddle is fairly common among certain brighter-than-average critics, and your misunderstanding, although in a sense obvious, is a relatively subtle one.
I've addressed some elements of it already:
http://farms.BYU.edu/publications/revie ... m=2&id=621But, of course, there's much more to be said. (There always is.) Trouble is, I don't have time (or the inclination) to do a one-on-one tutorial, especially when I'm not sure that you're really even open to learning on this matter, nor do I want to spend a lot of time on something like this for the small handful of largely hostile and, frankly, often quite unserious posters on this board.
But you've impelled me to consider, once again, writing a treatise on the method, logic, character, and scope of apologetics -- one, though, that would go considerably beyond what you've raised here and that would draw upon such disparate thinkers as Paul Feyerabend, Avery Cardinal Dulles, Peter Novick, Karl Popper, and the like. But the project that I've envisioned will easily take a year or two, at the absolute minimum. (Other projects beckon.)