??? I am a holder of HKID, "return home permit" and HKSAR passport. Everytime I go to China, I must use my HKID at the HK immigration, then use my "return home permit" to get into China at the Chinese immigration. When I come back, I use my "return home permit" at the Chinese immigration again, then my HKID for HK immigration.
The HKSAR passport is NO USE for getting into China (or Macau, for that matter).
They don't call 回鄉証 anymore. Instead, they are now called 通行証 which can be obtained from China Travel Services in HKG. Before I can get 通行証, I must get the SAR passport first. I was not born in HKG. 通行証 is a plastic card which looks like the regular Chinese ID card with passport-like encoding.
Last year when I went back to HKG, I just had enough time for the SAR passport. My next trip may go to China first then to HKG. It seems ironic that a legal Chinese citizen, having abode right in Chinese soil, holding a Chinese government issued passport, still requires visa to enter China.