SOVIET leader Mikhail Gorbachev conducted a dress rehearsal Friday for his summit meeting in two weeks with Western leaders in London. And he had a sympathetic audience - German Chancellor Helmut Kohl, unarguably Moscow's friend in court.Mr. Kohl emerged from a five-hour meeting outside the Ukrainian capital of Kiev with a pledge to support Soviet requests for Western economic backing. And Mr. Gorbachev took the occasion to warn that the only alternative to the success of his policies is the kind of civil war threatening to tear apart nearby Yugoslavia. "The events [in Yugoslavia] are a lesson for all the peoples of the Soviet Union, and also a warning," Gorbachev told reporters. "What is happening now should make everybody understand that it is necessary to pursue the road of renewal and not disintegration." Gorbachev's "warning" was aimed largely at the nationalist republics who still resist signing the draft treaty of union finalized last month. Six of the country's 15 republics have refused to sign. But more troublesome is the insistence from the powerful Ukrainian and Russian governments on even more concessions of power to the republics before they will endorse the document. Gorbachev is also subtly pressuring the West for support with the threat of the country's and his own political demise. He is hard at work on his July 17 presentation to the Group of Seven summit of industrialized nations in London. Contrary to earlier reports, senior Gorbachev aides say the Soviet leader will not present a full economic reform program in London. Instead, Gorbachev will give a detailed speech based on various economic reform programs, including the government's current "anticrisis" plan. "There will be a gist of the president's understanding of the processes taking place both inside the country and in the outside world," Gorbachev aide Yevgeny Primakov said. The senior aide rejected the charges from conservative Communists that Gorbachev will be selling the country to the capitalists and the expectations of those who believe that large amounts of Western aid will be forthcoming. According to reports, Gorbachev spent more than three hours of his meeting with Kohl "rehearsing" his London arguments. Kohl's aides, according to Reuters, say the chancellor gave Gorbachev "tips" on how to deal with individual G-7 leaders. Rather than government aid, Gorbachev is emphasizing foreign direct investment, with limited assistance tied directly to market moves. Gorbachev reportedly told Kohl that he will bring a list of projects needing foreign capital, including oil and gas production and modernization of nuclear power plants. The Soviet parliament gave final approval last week to a law on foreign investment which allows 100 percent foreign-owned subsidiaries to operate here. Mr. Primakov also referred to a request for commitme nts of food and consumer goods to help the Soviets survive a switch to free prices and a Western fund to back the ruble's move to convertibility. "It is absolutely clear that the civilized industrial world is banking on the fact that the perestroika [restructuring] processes won't take a reverse turn," Primakov told the government daily Izvestia on July 3. "Otherwise there will be either authoritarian power or disintegration of the Soviet Union with all its consequences." Kohl appears to buy this argument. He told reporters after the meeting that the success of Soviet reform is of interest to "all of us in Europe, because such success would serve the cause of peace." He said Germany would back associate membership in the International Monetary Fund with full membership to follow in the near future. Such status is considered essential to giving Western investors the confidence to put their money into the Soviet market. In an interview published yesterday in the German newspaper Welt am Sonntag, Kohl warned Western leaders against giving a lukewarm response to Gorbachev's call for cooperation. "It would be dumb for Western states to just lean back and watch how things develop in the Soviet Union and dumber still to speculate on its collapse," he told the paper, Reuters reported. "We - not only the Germans, but all Western states - must help the reformers. The Soviet Union must create the conditions for this, but we cannot stand aside." Gorbachev emphasizes that he is not going to London as a supplicant, but as the representative of a great power that offers a new vision of cooperation. "We are not seeking charity but cooperation on a mutually beneficial basis," he told visiting Mexican President Carlos Salinas de Gortari on July 4, according to the official Tass news agency. He warned that the changes in East-West relations remain "fragile." Over the weekend, President Bush sent Gorbachev a message urging a speedup in efforts to conclude a strategic arms reduction treaty that could be signed at a Moscow summit as early as this month. Disagreements over the treaty have delayed a summit. "Everywhere - in the USSR, the US, Western Europe, and in NATO - there are not only supporters but also opponents of changes," Gorbachev said. "The whole world needs restructuring, although some people in the West insist only the Soviet Union, only Eastern Europe must change. Everyone has to learn to respect the freedom of choice and to avoid imposing their own model of development on others.... It is with this philosophy in mind that I am going to London."