Voice guidance after head unit replacement.. Possible?

OK, sorry if this has been discussed, but I've searched, and can't seem to find a thread discussing the matter. I have a 2008 Prius and replaced the factory 6CD unit with a JVC DVD KD-AVX44 unit. Although it was definately a squeeze, I managed it. The dash kit had to be cut out a lot but was able to fit it in. If only the factory unit had a USB input, I would have never done this, but that is what I needed. I'm totally happy now, with the exception of the missing voice guidance. Now I know there has GOT to be a way of getting it back. Obviously it's injected through the factory head unit and must be still available from one of the factory plugs. I cant' seem to find a pinout showing this though, has anyone successfully gotten it to work after replacing the factory stereo? I know that on some Toyota vehicles it can be tapped into using a seperate amp/speaker. I've seen mention of using a powered PC speaker as a cheap method of tapping into the signal. Any help would be appreciated in this matter. Thanks!

RickH :noidea: