Just to clarify: in this case it may be okay if you're doing work for a client outside of the US and they are billed by a business entity that is also outside the US? So the deal-breaker is doing work for US companies?
Might not be that easy esp if your o/s entity still has you as a shareholder/owner. And if that country has a taxation treaty with USA like Australia does. Then you need to reveal all your foreign activity.