I'm also using XP64 (English), i've got a french version of XWA and an english version of Tie Fighter (Collector's CD-ROM).
I've tried to install TFTC choosing both Tie Fighter CDs but both failed to get me the correct sounds. I also have no inflight voices... I've also tried to install TFTC on a clean install of XWA (i had DarkSaber's craft pack installed) but it's the same.
You will need to start game wilth TFTCLauncher.exe to get sound correct, it's actually a no-cd patch that will make xwa search audio files from HD instead of CD. Please go to www.xwaupgrade.com/ there should have more people help you.