New Orleans--Commerce One Inc. said Tuesday that it has signed deals with Microsoft Corp. and Citigroup Inc. to enhance b-to-b commerce services. Commerce One said it has partnered with New York-based Citigroup Inc.'s Citibank to provide invoicing, payment and foreign currency exchange services to marketplaces. With Microsoft, Redmond, Wash., Commerce One will develop and market software that allows small businesses to link into exchanges using familiar Microsoft software applications. Combined, the two deals will produce systems that could reduce by 50% the average $30 transaction cost attributed to the 6.1 billion U.S. invoice payments that are handled manually by businesses today, said Mike Micucci, VP-solutions strategy for Commerce One. The announcements were made at Commerce One's eLink user conference under way in New Orleans.