The answer is no (Having a Home-Return Permit does not mean you are a Chinese Citizen).
In Hong Kong, the only authority to determine Chinese citizenship is Immigration Department (Not Guangdong Ministry of Public Security - One country, two system).
Somehow what is funny is you are not supposed to be a Austrian citizen and Immigration Department denies your application. So what you should do is contact the Immigration Department with the proof that you are a Chinese citizen (like your parents' HKSAR Passport copies, birth certificate and so on).
2011-04-05 04:34:51 補充:
Let me ask you this - is any of your parents a Austrian citizen (which will make you a Austrian citizen)?
2011-04-05 17:51:00 補充:
Very simple - work visa (If your parents are working under a visa).