PDA Bluetooth connection to Car Kit. Qaulity disgusting

Hi All..

I have an ETen M600 PDA (running Windows Mobile 5) and a Sony HCB300
carkit. The carkit worked perfect for the Sony Ericcson K600i mobile
phone, but not for the PDA.

The ETen connects to the Car Kit fine. The PDA picks up the Sony
Bluetooth device as a Bluetooth headset. I dial up a friend for
testing. He answers which I can hear him perfectly, but he can hardly
hear me at all, even when I am shouting. If I turn the gain up on the
microphone setting on the PDA, the friend tells me that the sound is so
bad, but still the same low level.

Is there anything special with a PDA and Bluetooth Car Kits to get them
to work like a normal Phone to Car Kit connection? Is this a problem
with Windows Mobile 5? I havent been able to try it with another PDA
phone to see if it is the Car Kit/PDA connections or not...

Any discussions appreciated.

Thanks,
Robert