Are the Xfce icons themable?

[Andrew Conkling]

I tried adding some icons to my icon theme of choice with (what I
thought were) the appropriate names as given in the Rodent theme
(xfce-*.svg).  However, even after a restart of Xfce, the icons did not
change to those in my theme.  (I'm speaking of those in the Settings
manager; I have xffm themed.)

Are the icons in Xfce themable?  Do they 'listen' to the GTK icon theme?

Thanks,
Andrew