Sony Bluetooth Headset BR-BT22 and iMac

I can not used my Sony Bluetooth Headset BR-BT22 with my iMac (see model and software version underneath). While I can set it up and it is found whenever I try to connect, it fails and suggests to not use this headset.

Same happens when I use them with my Macbook Pro.

It used to work on my Macbook (iMac is new) when I used OSX 10.5.xx but now I am on 10.6.4 on both machines ... BUT the quality was quite miserable.

I can connect to this headset from my iPhone 3GS and the audio quality is excellent!!!!! ?????

This is really annoying and does not make much sense to me?

Is anyone out there having found a solution to this problem?

Thanks Petra