Technical Series 8 steering wheel controls

[rossmangin]

Hi. I am fitting an aftermarket double din stereo to a near new Series 8 Ducato motorhome (Dethleffs build). We are using a Connects2 kit to enable the steering wheel controls to be used. I have been able to get the volume controls on the rear of the steering wheel to work but not the phone buttons on the front.
The stereo is a Kenwood 80202S.
Any suggestions why this is not working as it should?
Thanks