I dont know if there was a discussion before on this, but in my opinion kmail should depend on kleopatra oder display a text to do so manually. If kleopatra is not installed, the options "tools -> certificate manager" and "tools -> gnu pg log viewer" are greyed out (and do not work, because they start kleopatra programs). Reproducible: Always
I forgot to mention my kde version: it is 4.3.3 .
Fixed in the overlay. Thanks for the suggestion.
Applied to main repo, thanks.