If you have a file in your UI folder called "eq2ui_mainhud.xml" add the following lines to it:
<include>eq2ui_mainhud_voicebar.xml</include>
<include>eq2ui_mainhud_voicebar_popup.xml</include>
<include>eq2ui_mainhud_voicechat.xml</include>
<include>eq2ui_mainhud_voiceoptions.xml</include>
Have fun