Eloa,
Instead of putting everything inside the eq2ui_mainhud.xml, i recommend you put in
<include>eq2ui_mainhud_custommap.xml</include>
and put all your stuff in eq2ui_mainhud_custommap.xml, obviously
just makes more sense that way. Plus if people have certain windows listed above others it would change their layer order all to what your eq2ui_mainhud's order is.