you can go to submit your visa application to Cameroon consulate in Hong Kong. Requirements are Passport, at least 6 months remaining; 2 Visa Application Forms, fully completed and signed; 2 Passport-type photographs required; Completed Cover Page and Credit Card Authorization forms (print from browser); International Certificate of Vaccination for Yellow Fever; Copy of round trip airline tickets or itinerary, or letter of confirmation from travel agent; Copy of recent bank statement or letter from bank verifying applicant has sufficient funds.
Generally, the processing time is 7 working days. the fee is about US$50.00 Per Visa.