It's easy to open touchpad's case without breaking any of the clips. I've had to do it a couple of times because i want to repair a lcd cable /succeed :-) /.
I've opened it with a plastic knives from ikea -kalas- plastic is tough enough to pry the case, and soft enough not to break it or scratch it. You have to had 2-3 of them. it is easier at the first time to have a couple - about the same number as a clips :-) - so 8 will be excellent - pieces of plastic 1x2 cm - i've cut an old credit card - to lock the tabs in place while the lcd is still down there.
The 'secret' of not breaking the tabs is to put the knive beetween rear case and rubber seal near the tab, and lever the tab out of the hole in the screen assembly using a needle, paperclip, or anything else small enough. When the tab is levered, off the hole, it will ,click down' you can put aftermentioned piece of plastic on that place.
I hope that my post will be undersandable :-) so.. sorry for my english.