How I can have hong kong visa before 20/12/2011?

I am a Bangladeshi and I live in Italy about fifteen years with stay permit of Italy.for visit I like to china and hong kong .so I have air ticket Italy to Dhaka and hong kong to Italy.also I have the visa of china.but when I try to have hong kong visa they say me they need at list six week for give visa.but I hope from Bangladesh ambassy of china who work for hong kong also I can have visa in four working days.if it is possible to have the visa before 20/12/2011i can be in hong kong also for my holidays,thanks.