That's right. You'll have to pop the back piece off each time you want to dock it.
As for getting the Invisibleshields on, it is really hit or miss. I put one on my Blackberry Curve, absolutely no problems, on the first try. I went through a handful of screen protectors when trying to put one on my iPod Touch (which has a glass screen) and never was able to get it right. I eventually gave up on keeping a shield on the iPod and still never had a single scratch on that glass screen.