how long would it take to get a Hong Kong visa in Sri Lanka . I am a Pakistani with a Sri Lanka residencec visa.

I am a Pakistani National and living in Sri Lanka on residencec visa as I am working for MNC. I have a travelling coming to Hong Kong in Oct 2011 and it is going to be a business trip. Our HKG office will send an invitation letter for processing of visa etc.

I would like to know how much time would it take to get the visa.