With standard XP drivers was my headset, Plantronics Voyager 520 not to join. The installed with the drivers stack is recognized though and it works somehow, but in the comfort of Windows 7 it is not ran by far.
After several attempts with XP and 7, both with the drivers by Hama / Toshiba and Windows standard, it was impossible to produce noise-free transmission with my headset.
Conclusion: Not suitable for data transmission ok, for VoIP.