I packed the extra skins separately as there's a limit to 4 liveries in GTA IV. (Meaning no more than 4 liveries will work in-game)

To install, use OpenIV to import the skins to the bus.wtd found in your vehicles.img folder.

Make sure you do this AFTER the bus mod was installed!

You can swap the ones in this folder around with the ones already included in the .wtd

Just rename them to the ones already included in the .wtd, e.g. bus_sign_1, bus_sign_2 etc.