Hi, PCG,
I am a bit lost with your terminology. When you say "flash work" you mean Adobe Flash coding? If that's what you mean, then the answer is: The intention of Quark Interactive Designer (built into QuarkXPress 8) is to create Flash (SWF) and NOT require any coding. That makes it easy. It's Flash (SWF) for Designers.
That said, there might be things where coding is required (as you create a complex game or an Internet shop). There you probably need a coding environment like Adobe Flash. Good news are, you can export SWF out of either application and import it (as a movie) into the other. So you could work with both depending on your requirement.
Back to your job requirement.
My Chinese isn't that good, so that I am sure I saw the whole site. So without garantuee: What I saw is possible to do with QuarkXPress. So Page navigation, Movie Players, embed video, menus, sound etc. The only thing I noticed which is not possible is the page flip (curl) effect when advancing pages in the brochure. There are other effects available in QuarkXPress, they might be sufficient.
Give it a try, the Test Drive is free of charge and works without restriction (also with Chinese typography) for 60 days:
http://8.quark.com/evaluation.html
The Test Drive also exports SWF (= Flash).
Best
Matthias