If I understand your issue correctly, you need the prof of your course next term to sign a waiver allowing you into his class. If so, here's what I would do:
1) Try to build a case around your understanding of the pre-req material: If you took courses (that you passed) that covered similar material, highlight those. If you can see the connections between the pre-req course and the course you are taking next term, explain these connections to the prof, and show that you understand the concepts in the pre-req course that will allow you to establish a foundation for the new course. At this time, the prof only sees a D, and so assumes you will not be able to keep up in the course.
2) Think about why the chinese prof is acting "cantankerously". He may be someone who is used to hard work and good results. He may not see that people can understand the concepts within a course, but still get bad marks (procrastination, bored/unchallenging, personal crisis, overloaded schedule, etc).
Remember, the prof owes you no favors. Begging might make him despise you more. Go in humble, but firm. Understand that it is his right to not sign the waiver - you have to make him see that you are deserving of taking the course.
Good luck!
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