Install mouse cursor theme in xfce 4.2?

[Andrew Robinson]

I have 2 machines, one with debian & xfce 4.3 and one slackware with xfce 4.2.

I have installed a mouse cursor theme on 4.3 using the mouse settings
panel in 4.3 just fine. That tab doesn't exist in 4.2. I tried setting
it manually using ~/.config/xfce4/mcs_settings/gtk.xml:

        <option name="Gtk/CursorThemeName" type="string"
value="PolarCursorTheme"/>
        <option name="Gtk/CursorThemeSize" type="int" value="24"/>


Now firefox (gtk app I guess) shows the right cursor but not much
else. What is the way to set xfce4.2's mouse cursor theme?