Can not get my Plantronics CS-70 headset to alert on transferred calls( tried all 8 PRing patterns). It will alert on inside calls. I tried adding the ringer mic., still no alert. Plantronics says it is due to the interrupted ring beep beep of the transferred call. Is there a way to change the transfer ring to not be interrupted? Magix 4.0 with 4412 sets. I have 5 headsets on 5 different phones.