Virtutech Simics

Ah, you're right. Apparently they distribute custom versions for their clients, and they're all encrypted with twofish (hxxp://twofish.org). I can't say I know anything about it, except that it's 128-bit block encryption, and supposedly fairly difficult to crack. There's a little bit of discussion on it on RCE. I didn't realize that they weren't even downloadable because the one I tried to DL worked. I guess I just got lucky. Try package 55, it seems to be working. Of course, it's 100+MB and no guarantee about breaking the twofish crypto, but you never know.