Does this help:
At the w06 registry, at HKCU/ControlPanel/Sounds/RingTone0/ you can
set the default phone ringtone.
At the HKCU/ControlPanel/Sounds/KnownCallerRing0/ you can set the
ringtone for your contacts.
So, by default, the "sounds and notifications" control panel is just setting up "RingTone0"
Go there, set the ringer up the way you want it for Known callers (callers in your contacts list without caller-specific ringtones) and then, in a registry editor, copy all the stuff in RingTone0 into KnownCallerRing0. Now go back into the sounds and notifications CP, and change the ringer to something else. That will be used for *unknown* calls, while the other ringer (the one you set first) will be used for known calls, unless the contact has a ringer, in which case *that* ringer will be used.
Make sense? It has to, it's from Microsoft
