Hi again,
MADHEL is the official source for that. So SAMI / STI is the actual ICAO / local database ident that should be used.
Certain databases don’t support 3 letter idents, for those, artificial 4-letter ICAOs need to be generated if not published.
Argentina just needs to document the API link and make it available as controlled source to the data providers.
@ArgieFSPilot How did you get to that link?