Revert to snapshot on restart

I am a noob I have 59 days left on my 60 day trial of esxi 5 and vsphere 5.

I would like to have my guest OS revert to a snapshot on restart. I found that this can be done on Page 59 of the v.4 Administrator Guide. I cannot find this feature in v.5.

I have setup a WinXP, Win7, and Server2008R2 guest on my esxi 5 host. I installed VCenter on the 2008r2 VM, and I seem to have successfully attached to it. But I cannot find a way to revert to snapshot when the guest OS is restarted. The entry on the summary page/commands seems to be missing.

Thanks in advance

-Jim