to center the menu, it must placed in a container that is the same width as the menu, then apply margin: 0 auto; to the menu container.
so for example say you have a menu with 5 items in it, and the items are 100px each for 50opx width.
<div style="width:500px; margin:0 auto;">
<menu goes here>
if you are not able to get this working, I will need a link where i can see your menu.