Hi
In 2008(R2) click on Start and then use the "search field" to type "computer". This will give you the "Computer Management" and there you "Connect to another Computer (the NetApp in this case)...
On the CLI use this command (assuming your AD is named DOMAIN):
filer> cifs access DOMAIN\users "Full Control"
This will give the group users from the AD called DOMAIN the Full Control access on the share. Make sure to use the " " !
Peter