Mount ipod (external disk /dev/sda2) with a user belonging to the admin group

[Jordi Ferrando]

I have a problem with the ipod when mounted with another user (my wife), which 
belongs to the admin group.

When I connect the ipod with my user, I am asked if I which to mount it, in 
case I agree, it is mounted in /media/sda2.

When my wife logs in and connects the ipod, when asked to mount it and agreed, 
it displays a message like "Not an entry in /etc/fstab", but my wife belongs 
to the admin group, an according to the file /etc/soduers:

# Members of the admin group may gain root privileges
%admin  ALL=(ALL) ALL

Any idea? What permission is needed to mount a resource (external disk?)