You can use any regular tile or floor polish to shine the porcelain. It will not last long because the surface of porcelain is very hard and the polish flakes.
The haze on your high-gloss porcelain floor might actually be the wax or polish you're using. It is common that wax buildup has a dull look as it ages. Strip it off (the steaming should do that) then reapply.
Porcelain tile is a very hard surface. Any wax/polish you apply will just sit on top of the tile and will eventually wear or flake off. The haze you see may be caused by your water. Try using CLR on a small area to see if it removes the haze.
