Windows browser plugins

I want to run a windows only plugin on a web browser.
1) I've installed Firefox for windows, which I can run under WINE, but I don't know how to add a plugin to it. The downloader asks for a directory, and I don't know where to put it.

2) Can I use WINE to run a windows plugin on Firefox ruing native on LINUX?

3) I have a WINE application that opens a browser to access the inteet. I will only open the default browser. Is it possible to set the Windows Firefox as the default browser? I tried to set Windows firefox as the default browser using system settings, but is isn't listed. I tried to set Windows Firefox as the default browser from inside firefox, but it didn't work.

Thanks in advance.