Clean, Not Clean or Autoclean in protage

[Ravage]

First of all my problem:
I want to install an app, which is also installed as an older version.
Now I wan't both versions of this application installed together (they do not conflict) !

But when emerging the new version - portage will uninstall the old version

Is there an commandline option for supress cleaning ?

Or have I to set AUTOCLEAN="no" in make.conf ?? But this isn't what I want, because I've to set it back for all other apps.

May be this would work: