So you don't want to pay US Tax, is that it? You hiding something perhaps you don't want "your" IRS to know?
As an American you've always had to pay Tax on some of your money earned overseas haven't you? What's changed?
You'll get it back later won't you?
No different to what CX does with the Aussie based Pilots. We pay both HKIRD and ATO then get some of it back from the ATO later. ( they won't give credit for Provisional Tax and this means we are out of pocket $5 to $10K AUD until we retire )