The KB article I gave you is 4.3 only because it does a Screenshot. That was not why I pointed you at it.
Do you see the code it uses to write a sequence of bytes out? That code will work in 4.2.1. So all you have to do is copy that code, and turn your String into bytes (which you can do with getBytes()) rather than doing the Screenshot
FileExplorerDemo is very useful, because it will show you how to traverse directories, you might want to do that in order to check what files you already have, so you don't overwrite something.
I suspect that with these and the API documentation, you have enough to do the coding you require.
