If you want the dashboard command (task switcher) on your power button, this is what I did: add following lines to /etc/systemui/systemui.xml

<menuitem priority="999" name="Dashboard">
<icon>dashboard</icon>
<callback service="com.nokia.xterm" path="/com/nokia/xterm" interface="com.nokia.xterm" method="run_command" bus="run_command" autostart="true">
<argument type="string">dbus-send /com/nokia/hildon_desktop com.nokia.hildon_desktop.exit_app_view</argument>
</callback>
</menuitem>

This shows an additional button at the bottom when you press power button (I don't use icons though); if you click it it will open a terminal which will invoke the dashboard command. Haven't figured out yet how to do this without seeing the terminal window for a split second.

I'm mostly invoking dashboard through my cam button anyway though, which is much faster (shortcutd - http://www.my-maemo.com/software/app...to=1109&faq=42 ).