The FSUIPC tool may show a registration screen during installation, but this only requires your details if you have previously purchased a version of the tool. Otherwise it can be used in the standard "free" mode, which does not require a purchased licence. Simply click "not now" when asked to register, and the tool will allow you to use it in the standard mode.
To download FSUIPC for FSX Steam Edition please see the developer's website at http://www.schiratti.com/dowson.html