CCME ring tone for an ephone-dn

[Alex Tech]

Hi all,
i've an ephone-dn that i use for night service.
at night all the calls are diverted to this ephone-dn and some phones
(with a shared line matching the ephone-dn) rings.
Now i'd like to associete a ring to that ephone-dn so all the night call
could ring with a different ringtone
I found this document :
http://www.cisco.com/en/US/docs/voice_ip_comm/cucme/admin/configuration/guide/cmering.html#wp1010333

but i could not understand how to associate to the ephone-dn one of the
available ringtone i've loaded on the flash. The document above speeks
only about internal and external and "feature" ring (what does it mean
"feature"??)

any help will be appreciated

thanks in advance

bye

--
ALex