Hi Joao,
I have moved these posts together to make it easier to answer.
Steel Gold: When the file has downloaded, if it doesn't have an extension, just rename it to steelgold.zip (or simply open the file in WinRar...it works, I just tested it.
)
Legacy Postbit: It should... I used to run Legacy here. If it doesn't, let me know and I will fix it ASAP.
Branding Free - One site: That is correct. While you may use the Styles on any site you wish, the Branding free can only be used on one site per Branding Free licence.
Again, thank you for your purchase!