Now that I have Visual Voicemail on my new Iphone 4s, I noticed that I cannot respond to other Verizon customers at the end of listening to messages with a reply voicemail. With voicemail on previous non-Iphones I could hit 8 and reply with a message. It was a nice feature. Others cannot reply to me either - even when they get the prompt. Is this an Iphone, Visual Voicemail, or Verizon issue? Do you think this can be added to the system for Verizon to Verizon customers?