Hi
Everything should still go through the Canadian Trade office in Taipei. I'd that has changed they will direct you to the right office. Here is their contact info:
6F, Hua-Hsin Building, No. 1 SongZhi Road, Xinyi District, Taipei, 11047, Taiwan
Tel: 886-2-8723-3000 | General Email: tapei @ international.gc.ca
Have you and your family held resident status in Taiwan for over a year?
Lynn
As the office in Taiwan is closed as the OP noted. The sponsorship would go to Mississauga with the application and the application would be processed in Hong Kong.
http://www.cic.gc.ca/english/resources/manuals/bulletins/2011/ob308.asp