Does anyone know how to turn the sound off when the phone is powered on? I looked in the online manual and didn't see anything. I've been in the sound menu where that option can be found in virtually every other phone and found nothing. I had the phone on vibrate mode, yet when I powered it off then on, the phone played the sound rather than vibrate. I have been able to turn this off on all my phones. Wonder if anyone has figured out how to do it. Thanks in advance!