No Ringback Tone(message) in FreePBX UCP phone

Hi all,
Please help to resolve following issue:

I use last FreePBX stable version with asterisk 11, and I have enabled WebRTC phone in UCP. Everything is working, but there is one problem:

When I make outgoing call from my UCP phone I hear the same tone as my ringtone, i.e my ringback tone is same as my ringtone. Thant’s why I do not get the information that the customers is busy, unavailable or does not respond.
When I make a call with softphone or hardware phone I receive normal ringback tone or message if the subscriber is unreachable.
How can I get normal ringback tone in WebRTC phone?