WD Live Hub HDD *not* accessible when in standby mode

You’re in the wrong forum, for one thing.

The HUB forum is here:

http://community.wdc.com/t5/WD-TV-Live-Hub-Media-Player/ct-p/live_hub

But to answer your question:

If you’re using WIRED LAN, go look at the port’s LEDs.  If they’re OFF, you’re not putting it in standby, it’s being turned OFF.