Since you don't have fibre channel hardware, you won't be able to enable Xsan in System Preferences. You will need to load the Xsan launch daemon manually.
launchctl load -w /System/Library/LaunchDaemons/com.apple.xsan.plist
You should then be able to get a volume set up in Xsan Admin. I would only do this for testing though. Apple only supports fibre channel storage with Xsan.