[SOLVED] How to center a text widget in the header area

I thought this would be easy - it probably is, but I'm not succeeding at the moment.

I have a text widget in the header area. It is currently aligned left. I want it centered.

I've tried setting margin 0 auto; in various places - div.bfa_widget_area and div.textwidget - but the content remains aligned left.

The only thing I've found that works in a test is setting the container table cell to centered:

<!-- Header -->
<td colspan="3" align="center" id="header">

but I can't see how to apply this setting through options either.

What's the correct way to do this?

Thanks

Tim