In your custom UI folder find the file named
eq2ui_mainhud.xml and open it in windows notepad.
Once you have the file open in notepad scroll down to the bottom where you see the code...
Directly
above that line insert two new lines and add this...
Code:
<include>eq2ui_mainhud_guildcreation.xml</include>
<include>eq2ui_mainhud_lfg.xml</include>
Save the file and load up EQ2 and see if you get the new LFG window.