Supporting browser back buttons in web apps

Simple question. If I'm using a wizard in a web application (and the wizard has a Back button) and I click the browser's Back button instead of the Back button supplied by the web application, should the behavior be the identical?

Simple question, but the answer? Ugh.

There's a lot of discussion on this topic on the web, but interestingly the focus of much of the discussion is how to get users to stop using the Back button. Whether it be by providing them with back buttons in the app, adding breadcrumbs, or disabling the back button altogether. This strikes me as quite an odd solution to the problem.

At the same time, there are times when the back button is clearly inappropriate. If I have just finished clicking "Finish" in a wizard and I'm taken to a "Okay, here's what just happened" page, clicking the browser's back button is not a good thing.

But if the web app itself supports a Back button, why should it not also support the browser's Back button? And, if you agree with that, let me ask the next question. Should you be able to click the browser's Forward button and have it work like the "Next" button in the wizard?

My head hurts.