I know many have this problem, and to me it's still unsolved.
When connecting a USB-controlled-power-saving-outlet or a USB-harddisk to the laptop, the devices are still turned on even though the laptop is in standby mode.
I know for sure it is NOT a BIOS options: I have 1 laptop and 2 harddisks. Harddisk 1 with windows XP and harddisk 2 with Windows 7. The XP harddisk turns off USB outlets when going to standby, but Windows 7 harddisk in the same machine leaves USB outlets ON.
In the device manager i have set all USB deviced to: "Allow computer to turn off this device to save power"
In the Advanced Settings for Power Managment i have set the Selective USB-something to Activated.
Apperently nobody knows what to do.