There is a significant difference in the CCS install between '06 and '07, namely the Gen-II brake lights need the isolating relay for the CCS's purple wire almost every time. For some reason the Gen-II brake light wire doesn't go all the way down to zero volts when the brakes are off, and any voltage will keep the cruise from setting.
The wiring diagrams for the '06 and '07 are identical (at least for the UK variants). I didn't need a relay on my '06 or on my '10, both worked equally well.
The brake lights are very low resistance to zero volts, I'd suggest any relay requirement was for some other issue such as a poor ground run to the actuator. Or, possibly the ground return to the brake lights (spider?), but then I'd expect the ABS to complain since it also senses the brake circuit going to zero volts (ok, "zero" could be higher for the ABS than for the CCS100, but not much).