10.8 Server, how to sleep.....
This is what I did, (after mucho digging);
1. Clone my system first.
2. Run pmset -g assertions, to find out what's preventing the Mac from sleeping.
My list was constant and was really always two things. com.apple.serve and httpd. These had sub-processes being org.calendarserver.calendarserver, com.apple.server.filesharing, com.apple.ppp.pptp, com.apple.ppp.l2tp, com.apple.collabauthd. There were also com.apple.apache.denysystemsleep and com.apple.helpd.sdmbuilding being a sticking point.
I found out that helpd will not prevent sleep once it's finished what it's doing, so sometimes you'll be lucky sometimes not.
Apache on the oher hand I manually unload using sudo apachectl stop. This is something I'll have to look at fixing.
So I then set about finding these files and the reason it took so long was because I was looking in entirely the wrong place. Most of these are located at /Applications/Server.app/Contents/ServerRoot/System/Library/LaunchDaemons.
I then made the obligatory copies and set about altering the plists. Inserted them as necessary, repaired permissions and restarted.
Bob is your mothers brother. I have SLEEP!!!
PowerMac G6 Alu Cinema HD, Mac OS X (10.6), Ctrl, Alt, Del.........AAAaarggghhh!