I can't see /usr/local/share/xfwm4/themes/ in my Xfce 4.0.5. Why?

[Xan]

I have xfce4.0.5 and I don't know why, but I have themes 
in  /usr/local/share/xfwm4/themes/:

ls /usr/local/share/xfwm4/themes/
adept      coldsteel   gnububble  metabox       quinx        totem
agua       coolclean   gorilla    microgui      r9x          trench
agualemon  crux        gtk        mofit         redmond      triviality
alternate  cruxish     iceg       next          redmondxp    tux
atlanta    defcon-IV   kde        ops           retro        variation
atlanta2   eazel-blue  kde1       oroborus      silverado    xfce
b5         elberg      keramik    perl          slick
b6         fbx         kindaker   pills         slimline
beastie    g2          kleanux    piranha       smallscreen
biz        galaxy      koynacity  platinum      tabs
buzz       gaudy       linea      quiet-purple  today


but these not appear in xfce settings?. Why?

Thanks in advance,
Xan.