Keystone is, unfortunatly, indisputably dead at the moment. White Pajama Software bought it from Stonekeep, and promptedly turfed it in favor of their homegrown software. The source is "available", but it was never released under any kind of OSS license, so you're stuck with the last "official" release (which, while usable, still had tons of bugs and usability issues), and there's no active development going on right now.
For a while I tried WP's system. It was nice but buggy as all heck. And slow too. They supposedly would only support T1s - any problem I had was attributed to either my dialup or my cable modem. And when I requested SSL, performance went straight down.
I've seen nothing I like better, warts and all.
I switched to using RT - www.fsck.com - which is actually an extremely good system. - mz