Just northwest of Zhengyang Bridge, you can take a bus from the Fourth Ring Road to Fengtai Station, and then get off and go south. There is a restaurant in the Royal Dumplings Square, next to Beijing No.12 Middle School. If I remember correctly, I think it should be there. You can ask the security guard at that school over there. They must know it's nearby. I'll go there to get the certificate in a couple of days, hehe.