Xbox360 Vista Media Extender Driver

Hi, I'm Maurizio from Italy.
I have link my XBox 360 with my PC Vista Ultimate through a RJ45 Cable. My
brand new PC use MS Live One Care suite security, but with xbox360 settings
and turning off the firewall, after connection my PC find a new device, Media
Center Extender, and ask me Xbox360 Vista Media Extender driver, but Vista
Ultimate DVD, System32 folder don't contains a valid driver. From Xbox 360
i'm able to play music pictures and some wmv video from WMP11 shared folders,
but i can't connect my Media Center from my PC. Xbox360 customer care tell me
that it's a Vista trouble and i need a Vista patch file that is not providly
by xbox customer service. I have searched everywhere but i can't found
nothing. Help me please i don't know how resolve my trouble. Thanks