Lost connection between SE Z600 & Motorola HS801

Can anyone provide an idiot-proof guide to setting up my SE Z600 to connect
to a Motorola HS801 headset?

I can pair the devices. I can connect to the headset.But after 15-20 seconds
get a 'Bluetooth connection lost' message.

Is there something wrong with the setup that is not obvious?

How can/should I set up for handsfree use of the Z600, AND maintain the
connection?

Any help is much appreciated.

DG.