I can confirm that my T-Mobile MDA (HTC Wizard) WM 5.0 device works well with the BT TCU installed in my 2004 X5. Phonebook is downloaded and displayed on screen. I did not have to install any additional software for it. I am wondering if that is not the case with all WM5 devices ?

Edit: Nevermind, i just saw the additional stuff you can with the software mentioned in this thread.