Stock Stereo Aux input in palce of CD changer

let me summerize.
Wife has a Prius. There was a deal on Ebay where you can buy a unit that is Iphone, bluetooth, aux input that plugs into the place where the stock CD changer plugs in and you can use it. has anyone does this with the VX? I looked and could not find any posts or anything in side or out side of this forum.
I figured even if someone had a wiring diagram I would make my own pin out plug.
in my simple mind I figure you supply 12V to a pin in the back of the head unit and that tells it there is a CD changer and to turn on in inputs.
then just wire in a female headphone jack and you are all set, right?
anyone have the wiring diagram for the stock stereo?

i gor a nice cd player with all of that plus a usb port built in and a wiring harness from crutchfield for less than $100 with shipping - also came with a wiring diagram but i think i threw it away cause i didnt need it - they may have if on their website - suprisingly the instructions actually had the correct dash for the vehicross and showed where the screws are - handy for the first time unnecessary after that