I set up a command block to save-all at sunset and sunrise on a 1.5.2 sever and it saves tells all players it saved.
On my 13w22a server it dosn't work nothing happens.

If someone can comment on how the /save-on works that would be helpfull. dose the auto save only save on a server stop or in time like every 5min becuse i've had power outages that have lost many hours of work and I had used /save-on. Thats why I use /save-all.