> However, there seems to be an issue with produced
> filenames on disk ; I'm checking that

There is at least a charset bug:
<http://code.google.com/p/httrack/issues/detail?id=11>

... and a request bug :)
<http://code.google.com/p/httrack/issues/detail?id=12>

The site seems to expect browsers to change "\" into "/" (something non-IE
browsers won't do), fortunately httrack already does that

Thanks for this useful bug report!

EDIT: should be fixed in latest 3.47.13 subrelease