What you need to do is edit each contact for which you want to have a special ringtone. Access them in the phonebook, edit entry, select the "Store to" feature - choose "Store to PHONE", as what you want to do won't work on numbers that are stored to SIM. After verifying that the number is stored to phone, then select "Ringer ID's". Set this to "on". Once turning "Ringer ID's" on, you will be taken to a ringtone selection screen. Whichever ringtone you select will be the ringtone you hear when you receive a call from someone at that phone number. Hope this helps!