Don't mix filename and title tag. The filename is the identifier used by the filesystem, the tag is inside the file and can be read by dedicated players.
So: if you want to have a title tag then you either have to type it in or import it e.g. from the filename.
If you have a close look at your filename it has much more data in it than just the title. I take it that "06" ist the track number, miri_ben is the artist and then follows the title.
So it would not be a simple case conversion but you have to either strip the heading information or import that, too, into the right tags.
Then also: your filename does not use the "blank" as separator but the underscore. So you probably do want that to stay like it in the tags.
TO sum it all up: the whole action is not a case conversion.
What I would do:
a) import data from the filename into the tags with the Converter Filenname - Tag and a mask that looks like this:
%track%-%artist%-%title%
remove the underscores
Create an action of the type replace for the tags artist and one for title
(see /t/967/1
on how to create an action)
c) finally do your case conversion, also with an action: case conversion, normal.
If you still have questions about case conversion, there are loads of threads in the forum that deal with case conversion. Search for them.