i think that an -e option should be added like the one that konsole has. This will allow better kde integration. I noticed that kgpg does not support yakuake for this reason. I get an error yakuake: unknown option 'e'. There might also be other applications with the same problem.
*** Bug 337001 has been marked as a duplicate of this bug. ***
I created a patch for this. See: https://git.reviewboard.kde.org/r/124263/