I believe you are mistaken as to official international recognition of the South African Bureau of Heraldry's grants. At one time the College of Arms would register South African registrations in their Foreign Arms records, but that reportedly was ended quite some time ago on the grounds that South African arms did not imply gentility in the registrant.

Recognition by heralds of each other's grants is more comedy than comity, contrary to widespread assumptions. For example, the College of Arms will no longer recognize grants by the Chief Herald of Ireland, the South African Bureau of Heraldry, or Spanish cronistas. It also refuses to recognize Lord Lyon's grants to people domiciled in the Commonwealth outside Scotland, on the theory that the English kings of arms possess an exclusive "imperial jurisdiction." Lord Lyon won't recognize Canadian grants because Canadian rules allowing arms to pass through female lines means the surname and arms can get separated.

I commend Sir Crispin Agnew's essay "Conflict of Heraldic Laws" to anyone who is disturbed by all this.

--Break/Break--

I'm surprised you didn't hear back from the American College of Heraldry--are you sure you aren't mixing them up with the U.S. Heraldic Register, also mentioned earlier in this thread? The USHR has gone silent without explanation for a couple of years now.

The ACH also does design work. (Disclaimer: I'm not affiliated with or a member of the ACH.)