First you must export the ktorrent dbus session :
$ eval "export $(cat /proc/$(pidof ktorrent)/environ | perl -pne 's/\000/\n/g' | grep DBUS_SESSION_BUS_ADDRESS)"

It will open the environnement of ktorrent, split with new line instead of ascii 0 code char, then select the dbus session, then export in current shell env

Then you may manage ktorrent with :
$ qdbus org.ktorrent.ktorrent

ps : admin feel free to edit this post for most common use...

I was looking for a way to limit the global number of connexion in ktorrent, if someone has the qdbus command line i would appreciate it greatly