"Safari Zone (With Blocks After Levelled Up)" from serbii
http://www.youtube.com/watch?v=oSmDAF67f3k this video shows you how in more detail but im afraid it says in the video that you have to wait 70 days you have listen to the comentery im afraid otherwise you wont understand whats going on
to get lucario i beleive you lv up when riolu is happy and likes you during the day like espeon
i never liked the safari zone on ss so never went there but im not sure wether this works but you could always skip a few days by changing the date on your ds system