Hong Kong-born Australian citizen living in Frankfurt

Hi,

I wish to apply for a business visa to go to China in September. I was born in Hong Kong but emigrated to Australia as a child, and am now a naturalised Australian citizen. Now I live in Frankfurt.

It seems that in my case I need to supply additional documents because technically I am considered a former Chinese citizen. What would these documents be? For your information,

1. I have an expired British Dependent Territory Citizen Passport.
2. I have a HK birth certificate.
3. I don't have a Hong Kong ID card (because I was under age when I left HK)
4. I don't have my own naturalisation certificate for Australia (because I was underage, I was naturalised as a dependent of my father).

Thanks,

Puff