I already know about fuego ironworks, I'm using a PokeRadar, its just not working!?
The obivous is to just try and try again. You will find it about half of the time.
http://pokemondb.net/location/sinnoh-fuego-ironworks
Look here for more info.
When you use your Pokeradar, try going into the patches that short of sparkle white. That gives a better chance for Pokemon that you normally find in there to appear.
Type a Pokemon name, type, move, ability to see instant results.