problem in Vista home Premium using bluetooth headset

hi, I have gotten new laptop sony vaio with built in bluetooth with Vista
home premium. and also bought bluetooth headset of NIKKAI model # BES005 from
maplin electronics. I have successfully paired it with my laptop and I can
hear sounds but there is problem with its mic. Though it is properly
installed but mic is not working. I have checked this bluetooth headset with
Windows Xp on my other laptop and it works. So this seems that bluetooth
headset and mic is fine but mic is not working in Vista. Can any body help me
on this, please reply as quick as possible because otherwise i ve to return
this.