finding a wifi tablet

If you lose your Android phone you can send a text to locate it. If it is turned off or offline, it will respond to the text as soon as it is online (WiFi or 3G). For a WiFi only tablet, the only option is the web interface and if it is offline you get “command timed out”. The only option I can see is to keep checking which is not really practical. I know there is a solution to this because both Prey and Android Lost can send a message which is pending until the devices comes back online. Is there a way to do this with Avast?

Tom