default application for unknown mime-types

[Miroslav Suchy]

Hello,
I'm using Khtml for single task: open web page, take screenshot, close.
But if I open HTML page with some plugin/image/video which have unknown
mime type, dialog with option (Cancel | Save as | Open with) pop up. I
would like to avoid this window. I try to create dummy application like

#!/usr/bin/perl
while (<>) {}

and want to make it default application for unkown mime types using mime
type all/allfiles but without success.
Can somebody give me a hint what I should write to resource file?

Regards
    Miroslav Suchy