Since the ICS update, the power options are missing (high performance, normal, economy). Also the sleep feature. Does anybody know if the sleep option is available in ICS, or if there is a Play application that replaces the functionality.
Searching around the net I found this app. It appears that HTC disables the advanced Power setting for ICS. This app allows you to modify the settings. I just downloaded to test it out, hope it increases my battery life.
I'm not sure if this is what you're referring to as far as sleep, but if you go to Settings/Display, you can set the sleep time from 15 seconds to 10 minutes, or Never Turn Off.
As far as their power settings, I never liked their default Power Option settings and have always preferred to make the adjustments to my own preferences. However, I hope the app you found helps with what you want to do.