2008 ML - W164 - Bluetooth pairing

[Watchman]

I have a Blackberry Curve Bluetooth module in my ML which has worked with a BB Curve, a BB Bold and a BB Torch. Obviously only the Curve would actually fit into the cradle but the other worked nonetheless.

I now wish to pair my google Nexus 4 phone with the car. Given that it's all "just" Bluetooth, I thought this wouldn't be a problem but the Nexus won't pair. It sees what looks like a MAC address in the list of available devices but upon selecting it, it just says it has failed to connect.

Is it really in some way locked to Blackberry? If so, what's the solution please?