Thank you for your code MiK, it's really helpful! I like the idea of having only one controller action for all the steps, so it behaves as one page form.
It works in Virtual Host alright, but to make it work in a subdirectory of document root, you have to change the paths in views to make it work properly. This is a common problem. I managed that with the baseUrl() view helper, after setting FrontController->setBaseUrl().