The code they presented was this:
[custom-test_transfer]
exten => _X.,1,NoOp(Entering custom-test_transfer)
exten => _X.,n,Set(timeoutd=25) ; set timeout in seconds
exten => _X.,n,Set(extLeng=${LEN(${EXTEN})})
exten => _X.,n,NoOp(The extenlength is ${extLeng})
exten => _X.,n,Dial(Local/${EXTEN}@from-internal,${timeoutd})
exten => _X.,n,Set(CALLERID(name)=RB:${CALLERID(name)})
exten => _X.,n,Dial(Local/${BLINDTRANSFER:4:${extLeng}}@from-internal)
exten => _X.,n,Hangup()`
It actually does transfer the call back to the original extension, but hangs up the call. How can I fix that?