Actually, that is not how the HK exchange rate works. Its a function of share price in relation to market cap. City Telecom is listed in Hong Kong under the stock code: 1137. It is also listed in the US under Nasdaq ticker symbol CTEL. The market cap of this company as of 5/3/11 is 4.51B HKD which = 583M USD (since USD/HKD is trading at 7.73 today). If you bought 1 share of CTEL you would own 20 times more of the company that if you bought 1 share of 1137.
Now to the dividend. Since 1 share of 1137 represents 1/20th the ownership of CTEL you must first get parity between the two in terms of ownership, then bring the exchange rate into it. So, .165 HKD * 20 = 3.3HKD. 3.3HKD / 7.73 = .43 USD.
So you are due .43 USD per 1 share of CTEL.
Hope this helps. I have same issue with canadian companies i own that are dual listed on TSX and NYSE.