Thanks for your answers.
The rules state: "When a unit is beyond the Nominal Command Range of its HQ unit,
or that HQ does not exist, then the unit is considered Detached."
So, as Ricky B sayed, the higher HQs will ever be "detached" and their subordinates must be into their range to be shown in white.
The answer was in the Manual, wich I should have read thoroughly before, so my apologies for that, but maybe this may help someone else who had this same doubt.
Or maybe I shall wait for Hitler, who arrives at Dniepopetrovsk in mid february. Let´s see if he himself is "detached"