(un)mounting usb disk as non root user

[DSA - JCR]

Hi all

FreeBSD 6.2

I have made a copy system with USB disk and GELI for crypto.

Now, I would like that one non root user can login run a shell form
unmount the disk and change it, and then mount the new usb disk.

I have the shell script done, but only works if it runs under root.
When I tried to run under the user, I get

unmount /mnt/usb1  - Operation not permited

My user is in the group operator, but what more can I do?

I want to let them a script that in the login moment they can safely
change the usb disks.


Thanks in advance

Juan Coruña
Desarrollo de Software Atlantico