Using steering wheel controls with a new audio head.

Hi,

I want to replace the OEM audio head with a 2 Dim Sony AV type. The 'connect' socket on the new unit is a 3.5mm jack. There are 2 wires in the vehicle loom from the steering wheel controls (for volume, mute, mode, etc), one is the signal and the other the ground. If I wire these to a jack, would the new head react properly to the wheel controls? I don't see any instructions in the installation and user instructions on how to program the controls with the new head.

I see at Crutchfield, for example, one can buy a programmable adaptor, but these are not available in the UK (like a lot of things). But I'm wondering if that is an unecessary expense anyway.

Thanks for any help.