I would like to insure my foreign registered aircraft in the USA
You could do either or neither.

I assume you are flying a small, piston-engined aircraft. Any insurance company that insures turbine powered aircraft would have provisions for this. I don’t specialize in aircraft insurance. Having been in insurance for 20 years, I know that anything and everything can be insured for the right price. If your insurance company won’t do it, there are others that will. You just might not be willing to pay the price the insurance company requires.

The question you might ask yourself is how do people who ferry aircraft across the pond insure the aircraft? If you are planning a cross-Atlantic flight, you might want to contact an experienced, professional company to help you plan it. You have to think of more than insurance. Communication, water safety/survival and egress, auxiliary fuel planning, weather, sovereign airspace entry, enroute landing airports, customs, and other items need to be considered. 

An alternative is to rent an airplane or airplanes here in the US. I have run into a few of Brits, Germans, Aussies and New Zealanders who have done that. They made it seem surprisingly easy and something they did on a regular basis. Some annually. I have even checked into doing it in South Africa. It would have been simple with the renting organization even arranging for validation of my US pilot certificate for flight use in South Africa.