Installing a bluetooth car kit into Astra.

[AusAstra]

I'm fitting a bluetooth car kit into a 2000 Holden Astra (CD Model). Yes...I'm in Australia !!
The Astra is factory fitted with a Blaupunkt 520 which according to the Manual can be integrated with a car stereo. "Phone" appears on the display for incoming calls and The Speakers are used in place of an external speaker.

I can't seem to get any help through the dealers or phone installers.
I have installed many such kits in the past into different cars which come with standard wiring to do so.

If anyone has had luck with a Blaupunkt 520, do they have any suggestions?