By John S. McClenahen The U.S. now has until Nov. 1, less than a week before the presidential and congressional elections, to come up with an internationally acceptable substitute for "foreign sales corporations" (FSCs). Created in the 1980s, FSCs are a tax shelter that has allowed U.S. goods exporters to reduce income taxes on some foreign-source income. The World Trade Organization (WTO), acting on a complaint from the 15-nation European Union (EU) has ruled that FSCs are an illegal export subsidy under international trade rules. For a few months, the Clinton Administration and the U.S. Congress have been scrambling to come up with what they believe to be a legally acceptable substitute. The House has passed a measure, and legislative action is pending in the Senate. If the EU still finds fault, under terms of a U.S.-EU agreement made late last month and blessed by the WTO on Oct. 12, it will challenge the new legislation. And the effect, notes the Washington-based National Assn. of Manufacturers, will delay until mid-2001 sanctions against the U.S. that were originally slated to be imposed this past Oct. 1.