WASHINGTON (MarketWatch) -- Apple Inc. AAPL, -1.59% will tell a Senate Homeland Security subcommittee on Tuesday that it does not use "tax gimmicks" and that its Irish arm "is not a shell company." In testimony prepared for delivery, the company says it pays an "extraordinary" amount in U.S. taxes and that it's not opposed to paying more in exchange for a more efficient and flexible tax system. Apple's CEO Tim Cook is due to testify to the panel on Tuesday morning.