If you want to use a different windowmanager inside KDE4 than KWin, just follow theese steps.

First of all your windowmanager needs to have a proper .desktop file, so that KDEs control-center can recognize it. Next find the .desktop I’ve setup for Sawfish:

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[Desktop Entry]
Name=Sawfish
Exec=sawfish
TryExec=sawfish
X-KDE-WindowManagerConfigure=sawfish-config
#X-KDE-WindowManagerRestartArgument=--replace

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The file should be self-explaining. Next we need to find out where to place it:

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kde4-config --install data

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It will give us the directory, on my system it’s:

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/usr/share/kde4/apps/

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Now simply put your .desktop file into that directory. As the last step, open the KDE4 control-center (System Settings) and navigate to: Personal > Default Applications > Window Manager and choose yours from the Combobox, hit the “Configure”-Button to start it’s configuration utility.

Have Fun