I want to make kmail_view the default viewer for saved files which have a .eml file extension but kmail_view doesn't appear in the software menu as a stand along app. The only way I can use it is to right click on the file and select kmail_view from the context menu. If I make kmail the default app, it doesn't open the email, it opens kmail with the selected file in a sort of inbox menu where, with one more click, I can open the email. This is a little cumbersome and it seems to me that it shouldn't be necessary but I can't find anything in /usr/bin/ which looks like the executable for kmail_view. I expect there's some simple solution that I'd quickly find if I just knew how to ask google the right question but, thus far, my every attempt has been fruitless. Ideas? Thanks!

It is not a separate executable, but a command-line option of kmail. If you execute kmail --view <EML file> it works like you described (in fact, it's the command called by the file association).