apply S1 visa in hongkong?

Hi, I'm a Kenyan working and reside in China. I have residence permit and my wife is here with me. we have a son who was born in PRC. This year in February we traveled to Kenya and applied for my son, we got Q2 which can only be extended for 30 days instead of S1 type. can we apply S1 in Hongkong or we need to travel back to Kenya?