It's not available. I doubt there was enough demand. Most M5 owners like to have direct control of the throttle. I know I do. I have never used the cruise control feature, forget about active cruise.
2013 ///M5 Individual
Monte Carlo Blue, Platinum Full Individual Merino, Platinum Alcantara, Piano Black, Exec Pkg, Drivers assistance pkg, Bang and Olufsen, 20" wheels
Eisenmann Sport Exhaust, Bel STiR+, Laser Interceptor QUAD HP, Zaon MRX