回複：回複：額地神呀，不用這麽複雜吧

In my case, before I got the visa, I got a letter from the HK Immigrant office that told me my visa was approved and instructed me to put that little paper on my travel document once I received it. The TongXingzheng was indeed mentioned in both the letter and the visa, I was a little bit confused too, but since I was allowed to enter HK and stay for 7 days without any visa, so I just came and walked into the immigrant office...to apply for a temporary ID.
I think you should call the HK immigrant office.