Would Like to Visit Hong Kong on business trip

I'm a Sri Lankan currently llive in Japan working for a Japanese company and have valied Japanese visa for noext 15 months.
I would like to visit Hong Kong on a business trip for my company for 4 days
Chinese Embasy at Tokyo told me that it takes 4 to 6 weeks to process a Visa to Hong Kong.
I tintend to Arrive Hong Kong on 14th Dec. 2012 and stay there till 17th Dec. 2012
Is there any way I can aqure a Speed it for Hong Kong?