Was that function always there or only after Uberlingen?
If there is any ACC/UAC around that is actually downlinking RA/TAs then this must be a fairly recent development. I know that guys in Maastricht UAC have been working on implementing such a feature, but whether this has been achieved by now or not is not known to me a this time. Anyway such technology is, if at all, only available since short and certainly not at or before the Überlingen mid-air.