I have no idea, I'm still trying to figure out just WTH visual voice mail is, but I've been too lazy and I don't care enough to look it up
I just get annoyed by the texts I get whenever someone leaves me a voice mail, or when I check my messages, telling me I have Visual Voice mail...
But I've never seen a voice mail indicator on the phone, so that's the only way I know that I actually have a message