This is an interesting opinion piece written in 1974 which discusses the meetings of various people from South Africa and the US, http://kora.matrix.msu.edu/files/50/304/32-130-F09-84-al.sff.document.af000159.pdf. The noteworthy statements are;
“The State Department appears to have gone out of its way to bring or to assist in bringing to the United States large numbers of moderate African and Coloured leaders who can play a role in South Africa “progress toward majority rule.”
The names of Chief Gatsha Buthelezi, John Thorne, David Thebehali, Chief Clemens Kapuo, and Bishop Auala come to mind. Visits by moderate white opposition leaders such as the United Party’s Harry Schwartz have been judiciously offset by visits such as that of Nationalist Party Minister of Mines, Immigration, Sport and Recreation, Piet Kornhoof, schedule for early 1975.
The most significant visits, however, have been those of top-ranking political and military figures of the Nationalist government. In the 1960s, U.S. policy was to limit military contacts to inconspicuous correspondence courses or industrial courses at the War College. In a break with past practice, Kissinger in 1974 overruled Africa Bureau recommendations and permitted “private visits” by South African VIPs on military business. In January 1974, South African Minister of Information Dr. Cornelius Mulder, widely regarded as the likely successor to Prime Minister Vorster when the latter retires, met with Deputy Assistant Secretary of Defense, Vice Admiral Ray Peet, the senior officer responsible for International Security Affairs and the Indian Ocean, as well as with the then Vice-President, Gerald Ford. In May, the Chief of the South African Defence Forces, Admiral Hugo Biermann, a skilled propagandist for the strategic value of the Cape route, met with Admiral Thomas Moorer, Chairman of the Joint Chiefs of Staff, and with J. W. Middendorf, Acting Secretary of the Navy.”
“Press reports credit Donald Easum, Assistant Secretary for African Affairs, with helping to pave the way for recent top-level discussion in Lusaka between leaders of southern Africa’s white and black states. Rumors persist that Kenneth Kaunda, Julius Nyerere, and John Vorster have agreed to a détente scheme through which Rhodesia would peacefully move to majority rule in five years, Namibia would receive a carefully safeguarded opportunity for self-determination under at least formal UN auspices, and South Africa would show a willingness to “moderate” its own apartheid system.”
Keep in mind, Prime Minister H. F. Verwoerd of South Africa was murdered in 1966 and John Vorster replaced him. Also Kenneth Kaunda, became the Secretary General of the ANC in Lusaka in the early 1950s.