Hi there!
As far as I know the device can be activated at the device section, subsection system config. You just have to choose the device you want to start up and click on the "on" button shown above the device table. I don't know what the button is named exactly in your server version, I use the German version.
Funny, I have to do a technical research, too, because I get an error saying "The device behind the firewall or in local network can not be turned on."
I wonder why this problem occurs, because firewall and SNMP work fine on my device... maybe I'll figure it out. If I'll find a solution, I 'll write it down here.
Cheers!
Sabrina