Comment 3 for bug 296085

 I know this is rather old bug, but here is the fix for it in form of script for locking/unlocking
just call this script from blueproximity with lock unlock parameters as in screenshot attached

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#!/bin/sh
PATH=$PATH:/opt/kde3/bin:/usr/bin
echo ${KDE_SESSION_VERSION}
case "$1" in
        lock)
                if [ -n ${KDE_SESSION_VERSION} ] && [ "$KDE_SESSION_VERSION" -eq 4 ]; then
                        echo "KDE4 detected do the magic..."
                        ####qdbus org.freedesktop.ScreenSaver /ScreenSaver Lock #one way
                        # better way bellow (unified) - should work with gnome too (gnome users please test)
                        dbus-send --type=method_call --dest=org.freedesktop.ScreenSaver /ScreenSaver org.freedesktop.ScreenSaver.Lock
                        # Dear NVIDIA shitty drivers so don't use this one too often
                        ####xset dpms force off
                else
                        echo "KDE3 detected do the magic..."
                        dcop kdesktop KScreensaverIface lock
                fi
                ;;
        unlock)
                if [ -n ${KDE_SESSION_VERSION} ] && [ "${KDE_SESSION_VERSION}" -eq 4 ]; then
                        echo "KDE4 detected do the magic..."
                        dbus-send --type=method_call --dest=org.freedesktop.ScreenSaver /ScreenSaver org.freedesktop.ScreenSaver.SetActive boolean:false
                        # Dear NVIDIA shitty drivers so don't use this one too often
                        xset dpms force on
                else
                        # KDE 3
                        echo "KDE3 detected do the magic..."
                        dcop kdesktop KScreensaverIface quit
                fi
                ;;
        *)
                echo "usage of $0:"
                echo " $0 (lock|unlock)"

esac
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