I have SS, and I can't find a clue of how to get a Lucario. And I really want to breed it to get a Riolu.
Actually, there is a legit way to get Riolu in soulsilver. In the safari zone, there are items to place in all the free space in the surroundings. Just switch the safari zone to a place called Meadow with the area customizer. Next place 10 forest objects and 14 peak objects. Wait for 100 days and you will see Riolu in the meadow grass patch. This link can help:enter link description here