Have a look at the following that I think might help you out:
Menu > Layout > Position > Auto-Position Options
<div style="text-align:center">
... to be centered ...
</div>
But also have a look at the following link with a discussion about centering block elements for more info on this:
http://css-discuss.incutio.com/wiki/Centering_Block_Element[
^]
Good luck!