Sounds to me that you are confused as to what the visual voicemail is. From what I am reading, it sounds like you think that you will be able to read your voicemail rather that have to listen to them?
This is no the case. the visual voicemail is simply an app that allows you to access the voicemail without having to dial into a system, as well as pause, replay, delete, lock and forward at the push of a button.
Hope I got you right, and if not please clarify so that we can give you a better answer.