I might be missing something here.
I have not read at any point over the last few years that America actually WANT him.
My understanding was that his concern was based on being taken to Sweden and then extradited from there (This was why he would not travel to Sweden to be interviewed).
So have I missed something? Have the US actually expressed an interest in extradition? If not assange may as well have said that if Manning was released he would serve his time in a German facility - as far as I know they have expressed as much interest in imprisoning him as the US has.