5 years is right on with the transfer using Centrex. Stupid question: Are you calling in on a line that is ringing the auto attendant? Have you confirmed that you can manually flash the call and dial the intended source. I have found that on some co lines we can flash the call and attempt to send it (only on a incoming call). It sounds like the flash is working but hangs up after I release. In this case the co is not allowing the Flash Transfer. Check this manually. Also, don't try to test this by pressing "1" on your keypad and the outdial ID. No line to flash....