Power savings on USB Hard drives

[Laurent LEVIER]

Hi Guys,

I am using FreeBSD 6.2, soon 7.0 over a server and a laptop.

I would like, on both configurations, to be able to have hard drive 
power savings as on internal IDE drives.

At the moment, my external USB2 drive, when mounted but even not 
adresses, keeps running permanently despite it is just mounted for 
backups (no access out of backup times on sunday then).

I digged on mailing lists, but cant find why the HD keep running.

Can someone help?

Thanks in advance

Brgrds