How to disable iOS FaceTime notification sounds? I don't want any sound-based notifications on my iOS device, but I still want the visual alerts. 

Most apps (e.g. Messages, Reminders, etc.) have a None choice at the top of their list of notification sound options (or at least an On/Off switch, e.g. Gmail and Hangouts), but Settings / Notifications / FaceTime / Notification Sound yields no none option. 

Nothing more regarding notification sounds is listed under Settings / FaceTime, nor in the app itself (which frustratingly has no in-app settings—I think the system settings are crowded enough even without adding app settings to them). 

Am I missing something? 

In the meantime, all I can do (it seems) is disable FaceTime notifications altogether. 

2012 iPod Touch 5

iOS 8.0.2
I found this extremely frustrating as well. I spent an hour trying to record a silent ringtone in GarageBand but it consistently delivered noisey ringtones despite no sound on the track. I was about to give up when I thought someone else besides us must have been annoyed and figured it out. A Google search yielded the silent ringtone below. I tried it and it works great. Good luck.

http://www.codingmerc.com/blog/silence-ringtone-available-for-download/