asterisk users - Sep 2010 - rtcp to cdr for calls from dahdi to sip

Hello!

I want to get rtcp stats to cdr. (btw, I run asterisk 1.6.2.11)
There is howto here http://www.voip-info.org/wiki/view/Asterisk+RTCP
But I (and my users) do bridged calls from dahdi to sip, so in h 
extension channel is dahdi , and it doesn't contain rtcp stats.
There is info about function shared.
But I can't understand how to use it to put stats from sip channel to 
dahdi channel.
Could you help me?