As far as I know that radio clock is a Germany only thing. It's a module attached to the intrument cluster receiving the atomic clock signal from Braunschweig/Germany. You can enable that module with VAG-COM but maybe only if you have the module actually installed. If you are around Germany and close enough it may actually be retrofittable, ETKA should have the part number. To enable the radio clock set the 5th digit in STG 17 channel 19 to 1 (should be zero if you don't have the module installed).