webtoolkit application and default document

Hi,
I'm developing a WT (see webtoolkit.eu) web application. WT enables develop application as an isapi dll module. WT application can use so called "internal paths", i.e. when my application has e.g. TabWidget (http://www.webtoolkit.eu/widgets/basics/wtabwidget), I can write tab name in browser's address bar and application directly shows corresponding tab. When I don't write internal path, default tab is showed. But I have some problems. Everything works in IE 9 but not in Firefox,Chrome and Opera. When I try write internal path or press F5 (refresh) in Firefox (Chrome, Opera), I get error:

404 - File or directory not found. The resource you are looking for might have been removed, had its name changed, or is temporarily unavailable.

I noticed IE adds IIS default document to address bar, so when I write http://pq.upsserv.cz:8080/pqrepview ( my app address), IE rewrite this to: http://pq.upsserv.cz:8080/pqrepview/pqrepview.dll/ (pqrepview.dll is default document). When I manually append default document to address bar in Firefox (Chrome,Opera) everything starts working. I thing these problems are caused by bad configuring IIS. (we use IIS 7 on Windows Server 2008).
Do you have any ideas how to correctly configure IIS to avoid having to enter default document into address bar? Or do you think this may be due to some wrong configuration in WT?

Tomas