There is a bug with the VPN implementation, where it fails if you have special characters in the shared secret. We discovered this with the iPhone, and set up a special realm for it. I forgot all about it, since I stopped using it on the iPhone.
I found that it was just too much work to get to a terminal and login on the iPhone. It was fun to do a few times, but there is no way that I could get any real work done. I am hoping that I can at least get a little done with the iPad.