[Serusers] call transfer

Hi I have my ser.cfg all setup handling calls, pstn and all that...even NAT seems to be behaving itself :-), BUT call transfer doesnt want to work. Is there any special routing that needs to be done which should handle call transfer, or is another message sent, I mean do I need to set a route for NOTIFY or other MESSAGE type. A calls B (call is fine) B then transfers to C (again B and C can hear each other) then when B hangs up A and C arent talking, and it seems as if B hasnt really hung up (maybe this is where the problem is) In order to debug this when using ngrep and SER end, I am wondering which IP address a,b,c to monitor or should it be all 3 Iqbal