I don't know so much anymore, I know that in phase 1 it was like that, if the navigator radio was chosen, the radio installation branch changed, causing a partial change of the vehicle's branch, the CDX0 used at least in Vectra C this information from the BCM, so I imagine that they are standard radios and they will be the same in all cars, since it is not a separate circuit but rather the bcm gives it, the only thing that occurs to me is to see where the CD30 takes the info from and see if luck is in changing some pin of the gid, that I am going to doubt, because all the CDX0 go with can bus, look for the OPEL (which will be vauxhall for you) TIS that is the program of electrical diagrams and to see if there you have luck in the subject