visa enquiry

hello sir
i am a manager of a security items sales company 'cctv solution' and also owner of a export import co.we usally collect our product from singapore and india.one of a chinese manufacturar company sent me invitation early this month (tomb cleaning vacation time)to visit his factory to make a business deal.but i was very busy here and no time to go to the embassy in time.but the shenghen co's marketing manager is calling me over phone every day. now i like to go to hong kong and china for a short business visa.please let me know how easy i can get a hongkong and china double entry visa and what necessary papers to enclose with the visa form.note that i have singapore, malaysia, thailand etc counties multiple visa in my passport.thanks with regards