I feel much the same way, we are adding our own navigation, as I really don't want to rely on the browsers buttons. But, in my case here, thats not really the issue. The real reason I'm jumping through all these hoops is because of the dynamically created "Add Child" elements on the page.
I guess the irrating part for me is that in FF, even with the page reload, it will keep the session variables as you described above. But of course, IE doesn't want to play nice. I've tried to re-intialize the page(call the JS function) through several diffrent means, but thus far no luck. I've looked on here and some other websites, and I'm not really sure even if I re-wrote the JS code that it would behave as I need it to.
But thanks for the input & suggestions. If anyone can think of another alternative solution to this, I'm all ears.