Yes ... yes indeed I can.

That works quite a bit better than generating 4 channels and getting
massively confused with what uuid does what... but now im stuck without
ringback again :-(.

In my conference dial string I send:
{ringback=\'%(400,200,400,450)\',transfer_ringback=\'%(400,200,400,450)\',
.... }sofia/internal/1001@xxx.xxx.xxx.xxx

A dump of all the channel variables shows ringback is set to

   <ringback>%25(400,200,400,450)%3B%25(400,2200,400,450)</ringback>
   <transfer_ringback>%25(400,200,400,450)%3B%25(400,2200,400,450)</transfer_ringback>

This seems ok to me but I still dont get any ringback.

Thanks again for answering all the anoying questions from the same guy
:-P,
Sias